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Is a Rambus Comeback in the Future?

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February 27, 2002 11:49:56 AM

The answer to the rhetorical question in a recent column here appears to be "No." /. references Anandtech who quotes EBN, which writes: "Intel Corp. in the second half of this year will drop its final Direct Rambus DRAMs support in new computer products, it was learned Tuesday at the Intel Developers Forum."

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February 27, 2002 4:02:57 PM

Well I heard from my uncle's cousin's wife's barber that the nephew's sister's cat's friend's owner's mother talked to the CEO of Intel's son's girlfriend's sister's babysitter that Intel is going back to EDO.

Intel is using DDR for it's Xeon servers at the end of the year, that is the only base for all of the wild claims flying around the net.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
February 27, 2002 5:28:26 PM

ROFL @ FatBurger!

Hey, I have an old P1 that actually uses EDO.

Hell, for that matter I still have a C=64.

I lost my TI-85 though. That still depresses me to think about. I never did manage to perfect my 'Breat Out' clone on it, but I was <i>so</i> close.

<pre><b><font color=orange>AROOOOOOOOOOOOOOOOOOOOOOO!</font color=orange></b></pre><p>
February 28, 2002 12:49:22 AM

i just read the article that says maybe tomshardware was wrong to bash RDram in the past. RDram is the future afterall so they now think.

My mind boggles at this lightening turnaround.

This site has gone from calling the RD people the anti- christ to labelling them future saviour of P4 tech.

It reminds me of their review of the MSI kt266 pro-r MB.
At first they were all aglow with praise and oohing over the obvious quality. Then, after i buy the darned board, they diss the old board and praise the new kt266A chipset.

I have always viewed tomshardware as an independent and credible source.

But, it seems i may just have to re-assess that view and do a 180 just like tom!

:( 
February 28, 2002 11:39:39 AM

IMNSHO, Intel will do what ever makes financial sense.

They can't release server boards for RDRAM because they need to be able to support up to 4GB of RAM and this is not currently possible as 512MB modules are currently the max (something of a connundrum if RDRAM is the "future"). Outfitting a motherboard with 4GB would require 8 RIMM slots and this is not currently possible or advisable because:
1) This would increase the trace length to exceed specifications or require exotic placement of the RIMM slots causing huge motherboard design headaches.
2) This would effectively quadruple latency - as RDRAM latency is the product of the latency of the slowest module times the number of modules in a channel.

Please note that the new 32bit RIMMS do not solve this problem; they are simply double-sided 16bit RIMMs - already a very common configuration in the SDRAM market; they will only help by allowing a user to install one at a time and taking up less space on the motherboard. The only thing that can solve this problem is a higher density RDRAM chip module. If higher density RIMMs become widely available, Intel may later release a RDRAM server chipset.

Current desktop motherboards only have two slots per channel (or 2GB limit with current 512MB RIMMS) so latency is only doubled in comparison when adding extra RAM. RDRAM currently only makes sense in short bus scenarios. Rambus is looking at widening the 16bit bus to 64bits to compensate for the degradation in latency that occurs in long/narrow busses; it has yet to be seen, however, whether or not this will lead to excessive heat and/or clock ramping issues. Prior to widening the bus Rambus will have to solve the current problem of RDRAM chip module density; they will have to double and then quadruple the density to remain competetive.

With current DDR-333 bandwidth already 66% faster than current shipping RDRAM PC800 bandwidth and 1GB DIMMs commonly available, Intel made a business decision with its server chipset.

The question that no one - not even Intel - seems willing to answer definitively, is whether or not Intel will take action to supplant their current P4 performance leading i850/i860 desktop and workstation chipsets with an equivalent performing dual-channel DDR version. Despite all of the arguements to the contrary, several vendors have shown that the physical limitations of a 128bit bus can be relatively easily overcome - the e7500 even has 6 DIMM slots. Current Intel marketing dogma says that RDRAM is faster for the P4 - although true in current shipping desktop & workstation configurations, not true in the purest sense; the server market will set the matter straight.

I think that Intel will continue to support RDRAM until it is no longer financially beneficial to them (and the same goes for any technology - including DDR). With RDRAM and the Rambus "alliance," Intel attempted to gain control of the CPU/RAM question, a battle that they arguably lost. Since it is not likely that they will take up the battle again soon - at least not in the open, it is anyone's guess where we will be in 2 years time.

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
February 28, 2002 4:33:33 PM

Quote:
2) This would effectively quadruple latency - as RDRAM latency is the product of the latency of the slowest module times the number of modules in a channel.

Do you have proof that the latency multiplies with the number of modules? I know it goes up, but I have a <i>very</i> hard time believing that it's multiplied.

Quote:
Please note that the new 32bit RIMMS do not solve this problem; they are simply double-sided 16bit RIMMs -


No they're not. I have double-sided 16-bit RIMMs sitting in my computer right now.

Quote:
it has yet to be seen, however, whether or not this will lead to excessive heat and/or clock ramping issues.


I doubt it will, as simply adding more pins shouldn't affect the internal workings of the chips. In fact, if it gets spread out as a result, it's possible that they would run cooler. But you could be right, we'll have to wait and see.

Quote:
With current DDR-333 bandwidth already 66% faster than current shipping RDRAM PC800 bandwidth


Hmm...2.7GB/s vs. 3.2GB/s. Nope, RDRAM has more bandwidth. Sorry.

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is whether or not Intel will take action to supplant their current P4 performance leading i850/i860 desktop and workstation chipsets with an equivalent performing dual-channel DDR version.


It would be much easier and more economical to simply introduce dual-channel using 32-bit modules, but if Rambus drags their feet introducing higher pin count memory, then Intel may have no choice. Rambus appears to be doing just that, with no new memory technology introduced in quite a while (excluding the 32-bit modules shown yesterday at IDF, which of course haven't been released to the public).

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
March 1, 2002 4:53:53 PM

Quote:
Do you have proof that the latency multiplies with the number of modules? I know it goes up, but I have a very hard time believing that it's multiplied.

It is simple mathmatics and part of the RDRAM spec. RDRAM is a serial memory technology, so any signal to the higher memory addresses has to traverse the other modules. The RDRAM spec requires pre-negotiation that limits EVERY call to the speed of the slowest possible call.

<A HREF="http://www.realworldtech.com/page.cfm?section=news&AID=..." target="_new">To put the "random access" back into a DRDRAM-based memory system, Rambus Inc. designed into each memory chip the capability of delaying the output of read data onto the channel beyond the normal 20 ns page read access latency by a programmed amount of 2.5, 5.0, 7.5, or 10.0 ns using the TPARM control register. When a DRDRAM-based computer system is powered-on or reset, the processor and memory controller ASIC perform an elaborate initialization ritual for each DRDRAM in the system. As part of this effort the read round trip delay for each memory device is measured and the longest delay is determined. Then the processor and/or ASIC attempt to equalize the round trip read access time for all devices by programming extra read delays into DRDRAMs closest to the ASIC. The net result is all DRDRAM devices appear as equally slow as the farthest device.</A>

Quote:
Please note that the new 32bit RIMMS do not solve this problem; they are simply double-sided 16bit RIMMs -



--------------------------------------------------------------------------------


No they're not. I have double-sided 16-bit RIMMs sitting in my computer right now.

Current double sided RIMMs do not function like current double sided SDRAM (DDR or SDR)DIMMs. Double sided DIMMs are usually dual bank; Current double sided RIMMs are still serial. The upcoming 32bit RIMMs more closely match current double sided DIMM technology; you get a full bank from each side. In the case of RIMM technology this means 16bit on each side (16 + 16 =32)<A HREF="http://www.anandtech.com/showdoc.html?i=1590&p=5" target="_new">The board layout is relatively simple, a single 16-bit RDRAM channel is routed to one side of the RIMM slots while another channel is routed to the opposite side of the slots.</A>

Quote:
I doubt it will, as simply adding more pins shouldn't affect the internal workings of the chips. In fact, if it gets spread out as a result, it's possible that they would run cooler. But you could be right, we'll have to wait and see.

Yeah, we will have to wait and see. The issue that causes more heat is more power to drive higher densities of transistors (what is required to develop higher density RDRAM chip modules). Unless the RDRAM process is drastically scaled down (SOI and/or .09 micron, etc.) the heat generated by the higher density chip modules (a RIMM is made up of chips that are in and of themselves modules) will require active cooling.

Quote:
Hmm...2.7GB/s vs. 3.2GB/s. Nope, RDRAM has more bandwidth. Sorry.

<A HREF="http://www6.tomshardware.com/mainboard/00q1/000315/ramb..." target="_new">See Table</A>

Again, do the math: PC2700 DDR333 has 2.667GB/s bandwidth per stick (333.333MHz * 8bytes = 2666.667MB/s). PC800 RDRAM has 1.6GB/s bandwidth per stick (800MHz * 2bytes = 1600MB/s). DDR SDRAM has more bandwidth. OTOH, as I stated above, RDRAM chipsets (i850, i860) double that bandwidth by combining two channels into one (1.6 * 2 = 3.2GB/s). The extra bandwidth is due to the chipset, not the memory technology used. The Intel e7500 chipset does the same thing with older PC1600 DDR200 SDRAM. So, DDR <b>technology</b> currently offers 66% more (2.667GB/s vs. 1.6GB/s) bandwidth.

<A HREF="http://www.anandtech.com/chipsets/showdoc.html?i=1588&p..." target="_new">The memory controller in the E7500 is validated for use with both DDR200 and DDR266 SDRAM however the bus will only operate at 100MHz (DDR200 speeds). This means that although you can use DDR266 SDRAM in it, your memory will always run at DDR200 speeds. Intel's reasoning behind this that dual DDR200 channels yield a theoretical 3.2GB/s of bandwidth to main memory which is perfectly matched up to the 3.2GB/s FSB. As we've seen in the past (take the KT133A chipset for example), a synchronized FSB and memory bus generally yields lower latency CPU/memory accesses than an asynchronous setup. It is very clear however that when Intel does move to a 133MHz (533MHz quad-pumped) FSB, a future successor to the E7500 chipset will support DDR266 SDRAM.</A>

Quote:
It would be much easier and more economical to simply introduce dual-channel using 32-bit modules

For Intel, Rambus and Samsung, maybe. But for consumers, when 32bit PC1066 * 2 (4.2GB/s) modules finally ship, how much will it cost? We can't even buy PC1066 yet and if Rambus tradition holds, it will cost an arm and a leg. Current DDR333 would already provide 25% greater bandwidth in comparable dual-channel configurations (5.3GB/s). DDRII will also probably be available around this timeframe.

<A HREF="http://www.ee.umd.edu/~blj/papers/memwall2000.pdf" target="_new">http://www.ee.umd.edu/~blj/papers/memwall2000.pdf&lt;/A>

So, I stand by my statement: it is nearly impossible to tell what memory technology will be in the forefront in 2 years time.

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
March 1, 2002 5:22:18 PM

I still have my Commedore 64 and my Commedore Vic 20. Donkey Kong still looks great on it.

<b>"Taurelilomea-tumbalemorna Tumbaletaurea Lomeanor" - Treebeard</b> :lol: 
March 1, 2002 6:03:51 PM

Do you have actual latency test results, though? I'm just trying to make sure that practice matches up with theory, since often it doesn't.

Quote:
The issue that causes more heat is more power to drive higher densities of transistors (what is required to develop higher density RDRAM chip modules).


True, I hadn't thought about higher power requirements.

Quote:
Again, do the math: PC2700 DDR333 has 2.667GB/s bandwidth per stick


Per stick? How about we pick something even more arbitrary and meaningless? How about bandwidth per watt of heat created? Or bandwidth per BMW owned by the executives of the manufacturer?

Quote:
how much will it cost? We can't even buy PC1066 yet and if Rambus tradition holds, it will cost an arm and a leg.


I highly doubt that. RDRAM used to cost more than it's weight in gold, and dropped significantly by the time PC800 came out. Nobody would buy PC1066 if it cost too much, it should release within 25% of PC800 prices.

Quote:
Current DDR333 would already provide 25% greater bandwidth in comparable dual-channel configurations (5.3GB/s).


And would also take up <b>four times</b> as much space on the motherboard as current RDRAM configurations. Of course, you're also assuming that there will be CPUs that can use that much bandwidth (or would you simply split the bandwidth, like on nForce?). For a P4 platform, that may work. Definitely not for an Athlon system (unless they up the bus to 166, like most people hope).

Quote:
So, I stand by my statement: it is nearly impossible to tell what memory technology will be in the forefront in 2 years time.


Oh, I completely agree. We've seen in the past year or two that consumers have a huge say in that (why else would Intel release the i845?), and since so many people hate Rambus the company, RDRAM's development may be choked simply by lack of sales, for one example.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
March 1, 2002 6:17:27 PM

Quote:
and since so many people hate Rambus the company, RDRAM's development may be choked simply by lack of sales, for one example.

I'm surprised that no DDR SDRAM zealot has as of yet gone and blown up Rambus HQ like some religious zealots have done to abortion clinics. ;) 

<pre><b><font color=orange>AROOOOOOOOOOOOOOOOOOOOOOO!</font color=orange></b></pre><p>
March 1, 2002 6:28:01 PM

Since you like using "quote" I will too.

Quote:
Again, do the math: PC2700 DDR333 has 2.667GB/s bandwidth per stick (333.333MHz * 8bytes = 2666.667MB/s). PC800 RDRAM has 1.6GB/s bandwidth per stick (800MHz * 2bytes = 1600MB/s). DDR SDRAM has more bandwidth.


Your math is incorrect.

PC2700 is DDR 166MHz. The end result was correct but the calculation is incorrect. 166MHz x 2(DDR) x 8bits = 2.672Gb/s

Now saying that DDR has "more" bandwidth is correct in theory, but not in the "real world." RDRAM is more efficient when it comes to "actual throughput" when looking at "theoretical vs. actual."

<b>"Taurelilomea-tumbalemorna Tumbaletaurea Lomeanor" - Treebeard</b> :lol: 
Anonymous
a b } Memory
March 1, 2002 11:53:10 PM

if RDRAM is so damn good, then why did Rambus need a special agreement with Intel to protect it from DDR when Pentium 4 was first released? trying to deny competition with sneaky tricks like that does not gain my trust. what i dont trust, i dont buy. i think a lot of other people feel the same, and that is all there is to it.
March 2, 2002 2:47:43 AM

If DDR prices keep skyrocketing (mind you, it costs nothing to make), they're going to piss off someone, and keep the gate open for RDRAM. Someone better get them back into check.

-Rick
March 2, 2002 8:01:11 AM

Quote:
Do you have actual latency test results, though? I'm just trying to make sure that practice matches up with theory, since often it doesn't.

No, but Rambus does - try prying them from their cold, dead fingers....

Quote:
In reply to:
--------------------------------------------------------------------------------

Again, do the math: PC2700 DDR333 has 2.667GB/s bandwidth per stick



--------------------------------------------------------------------------------


Per stick? How about we pick something even more arbitrary and meaningless? How about bandwidth per watt of heat created? Or bandwidth per BMW owned by the executives of the manufacturer?

'cause then it would be something arbitrary, like say, the things you listed...hehehe :tongue: Seriously, call it arbitrary if you like, but we are talking about existing technology here; existing RDRAM is 16bit - future RDRAM chip modules are still going to be 16bit - they are just planning on effectively "slapping" two RIMMS back to back and calling it a 32bit module. Measuring memory bandwidth stick by stick (or RIMM vs DIMM) is the only true and valid measurement one can take to answer the question "which one is faster?" Any other mesurement relies on other factors - all of which would have to be equal or equivalent to answer the question truely and scientifically.

Don't get me wrong here, I do know that current i850/i860 chipsets outperform current i845D chipsets - but that's the chipset, not the RAM.

Quote:
Nobody would buy PC1066 if it cost too much, it should release within 25% of PC800 prices.

We'll see - I think that it will be closer to 33-50%. Also, I was refering to 32bit (PC1066 * 2) for the arm and a leg part.

Quote:
In reply to:
--------------------------------------------------------------------------------

Current DDR333 would already provide 25% greater bandwidth in comparable dual-channel configurations (5.3GB/s).



--------------------------------------------------------------------------------


And would also take up four times as much space on the motherboard as current RDRAM configurations. Of course, you're also assuming that there will be CPUs that can use that much bandwidth (or would you simply split the bandwidth, like on nForce?). For a P4 platform, that may work. Definitely not for an Athlon system (unless they up the bus to 166, like most people hope).

Actually, it would only take up more space for the traces - something already proven doable and feasable - with the nForce (3 DDR slots with room for a forth) and the Intel e7500 P4 Xeon server board (6 DDR slots - two more than any RDRAM based i850 mobo). The slots themselves are no bigger than RIMM slots. I'm specifically talking about the P4 here - It's the only platform that uses RDRAM. The Athlon has no need for dual-channel; just like with the P3, the extra bandwidth goes to waste. Athlon w/166MHz FSB will be paired synchronously with single-channel DDR333 which perfectly matches its needs, just like dual-channel PC800 or PC1600 (DDR200) synchronously match with the 100MHz(400 effective) and dual-channel PC1066 or PC2100 (DDR266) will synchronously match with the 133MHz (533 effective) FSB of the P4 desktop and P4 Xeon server chips respectively.

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
March 2, 2002 8:27:37 AM

I will double quote you:

Quote:
Since you like using "quote" I will too.


In reply to:
--------------------------------------------------------------------------------

Again, do the math: PC2700 DDR333 has 2.667GB/s bandwidth per stick (333.333MHz * 8bytes = 2666.667MB/s). PC800 RDRAM has 1.6GB/s bandwidth per stick (800MHz * 2bytes = 1600MB/s). DDR SDRAM has more bandwidth.



--------------------------------------------------------------------------------


Your math is incorrect.

PC2700 is DDR 166MHz. The end result was correct but the calculation is incorrect. 166MHz x 2(DDR) x 8bits = 2.672Gb/s

Now saying that DDR has "more" bandwidth is correct in theory, but not in the "real world." RDRAM is more efficient when it comes to "actual throughput" when looking at "theoretical vs. actual."

I don't know where you went to school, Bum - sounds like maybe not at all...but you need to check your math. The number you gave was for 167MHz (NOT 166MHz) * 2(DDR) * 8bits = 2.672Gb/s - no existing memory spec I know of. The DDR multiplier was a given in my calculations - for both RDRAM and DDR - as they both are double-data-rate specs.

The actual 166Mhz spec is 166 2/3 or 166.6666666666666666666666666 etc. just like 133MHz really is 133.3333333333333333333333333 ad infinitum. 166.6666666666666666666666666MHz * 2(DDR) * 8bytes = 2.6666666666666666666GB/s as I previously stated (but only to 3 decimal places.

Also, you stated "Gb/s" which is gigabits per second - not "GB/s" which is gigbytes per second - and the real answer, in that case, would have been 166.667 * 2(DDR) * 64bits = 21,333.333 Gb/s as DDR DIMM are 64bits wide and are rated in "bytes" not "bits."

On the question of Theoretical vs. Actual, I would have to say that DDR has proven itself just as capable of using its theoretical bandwidth as RDRAM. In <A HREF="http://www6.tomshardware.com/cpu/02q1/020225/p42666-11...." target="_new">Tom's latest tests</A> the P4 was, at most, able to use 78.5% of the available RDRAM bandwidth (3346/4266 and 2518/3200). The Athlon was able to use 97.7% of the DDR bandwidth (2080/2133). Plus, DDR latency is lower than RDRAM latency (by almost half).

These tests seem to indicate that if anything, DDR is more efficient.

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
March 4, 2002 3:53:53 PM

Quote:
Measuring memory bandwidth stick by stick (or RIMM vs DIMM) is the only true and valid measurement one can take to answer the question "which one is faster?"


No, it's not. Because there aren't really any single-channel RDRAM platforms or dual-channel DDR platforms. Measuring by stick means nothing.
Measure either total bandwidth available in a platform, or bandwidth per pin. Measuring 16-bit RDRAM against 64-bit SDRAM might show what current platforms consist of, but it falls far, far short of showing what the differing technologies are capable of.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
Anonymous
a b } Memory
March 4, 2002 9:24:01 PM

I have seen at least two companies, Dell and Colfax international offering 4 GB of RDRAM. Why do you say that it isn't possible?
March 4, 2002 9:27:35 PM

Can you provide a link?

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
March 4, 2002 9:59:47 PM

Thanks for the link, they use a riser to provide 8 RIMMs.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
March 4, 2002 10:23:44 PM

From the Dell link, configure the PC and pull down the RAM menu to where it says 4GB. It says "riser" in that option, and I think one or two others as well. I didn't check the other link, I assume it's the same.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
Anonymous
a b } Memory
March 4, 2002 10:29:46 PM

I don't think it's the same. At least not that I can tell.
March 4, 2002 10:34:38 PM

The Colfax one has 8 RIMMs, so it must use a riser.

Did you even look at the Tyan board? The second picture is of a RIMM riser.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
March 5, 2002 5:17:32 AM

Quote:
Because there aren't really any single-channel RDRAM platforms or dual-channel DDR platforms.

The i820 and i840 are both examples of single-channel RDRAM platforms. The nForce Athlon platform and the e7500 and Serverworks GCLE P4 Xeon platforms are all examples of dual-channel DDR platforms. Isn't it strange that none of them support the P4 desktop platform? Dual-channel (and quad-channel - GCHE) DDR platforms are the highest performing memory platforms available - with the notable exception of the nForce (the only non P4 platform listed).

Intel is obviously avoiding using the higher performing DDR dual-channel on P4 desktop and it has nothing to to with technological limitations.

Quote:
Measure either total bandwidth available in a platform, or bandwidth per pin.

LOL

People don't buy pins of RAM, they buy sticks. Bandwidth per pin is only a valid comparison with similar technology; RDRAM is serial and DDR-SDRAM is parallel. That's like saying that Serial ATA 133 is higher performing than UDMA 133 because Serial ATA only takes 4 pins while UDMA 133 takes 40. Serial ATA may scale higher than UDMA because it has fewer pins, but there aren't yet any platforms to prove it. RDRAM should have the same benefits, but it hasn't yet been proven. DDR sticks and Dual-channel DDR platforms already outperform dual-channel RDRAM in pure memory bandwidth. Oh, and about the arguement of 1GB RDRAM sticks and 2GB maximum, multi-channel DDR platforms offer up to 16GB.

This is obviously (unless you're wearing Intel/Rambus blinders) a political issue.

We'll just have to wait and see how long Intel holds out.

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
March 5, 2002 5:21:12 AM

Yes, they do exist, but since RDRAM is a serial technology, lantency increases factorially for every stick you add in per channel (i.e. 8 sticks have quadruple the latency of 2 sticks).

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
March 5, 2002 3:12:28 PM

If ATA wires were embedded in the motherboard, then yes, that would be valid comparison.

I'm talking about comparing memory platforms that take up the same amount of space on the motherboard. Quad-channel 32-bit RIMMs would be the same as dual-channel 64-bit DIMMs. They would also provide a theoretical 12.8GB/s of bandwidth. Oh, you're right. SDRAM is the better technology after all. 4.2GB/s of bandwidth is way better.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
March 5, 2002 6:53:42 PM

Trace space on the motherboard, while an important factor in design and layout, is not the critical definition of "performance" in such systems. Yes, trying to fit more traces into a design can cause difficulty and extra cost, and reducing those traces can alleviate some. This is one of the areas that Rambus addressed in designing RDRAM. OTOH, there are so many other factors involved.

Since RDRAM is a serial technology, while having some of the theoretical benefits of such, it also inherits all of the difficulties and flaws of such a design. As technology advances those issues can be overcome or work-arounds can be developed to compensate for them. RDRAM is just on the cusp - currently still on the up-hill side.

Oh, and BTW, ATA wires (traces) <i>are</i> embedded in the motherboards it is implemented on. The cables we use are simply flexible extensions.

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
March 5, 2002 9:26:03 PM

Quote:
Oh, and BTW, ATA wires (traces) are embedded in the motherboards it is implemented on. The cables we use are simply flexible extensions.


Heh, you're right of course. I'm an idiot.
I wonder if motherboard makers will make any changes, due to the extra space? Suddenly going from 80 wires (two ATA100 channels) to what, 8?
I wonder if that'll change layouts or sizes at all.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
March 5, 2002 10:45:04 PM

Quote:
I wonder if that'll change layouts or sizes at all.

Yeah, they'll use the extra space for dual-channel DDR...heh heh

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
March 6, 2002 1:59:11 AM

I figured you'd say something like that :tongue:

I was trying to think of other features they could include, but most stuff I thought of is already available, albeit not always widespread. Onboard sound, video, LAN, RAID, etc.

Hmm...maybe a huge L3 cache? I don't think I want to go back to the days of cache on the motherboard, though. I don't think it'd even be very feasible, business-wise (not for home computing, that is).


<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
March 6, 2002 8:29:25 AM

Burger, I just read this whole thread, and you sound like ray!

:-)

"The Cash Left In My Pocket,The BEST Benchmark"
No Overclock+stock hsf=GOOD!
March 6, 2002 11:39:13 AM

I still say that they should use that extra space on the motherboard to move some things around and implement optical to eletrical converters to run the entire motherboard off of optical busses. That way hardware will be all the more prepared for the concept of optical chips, and the busses on the motherboard will no longer be a limiting factor to overclocking.

But then, I'm insane.

<pre><font color=green>//error-proof coding</font color=green>
<font color=blue>void</font color=blue> main(){<font color=blue>return</font color=blue>;}</pre><p>
March 6, 2002 4:46:49 PM

Yeah, I was thinking the same thing, actually. We have roughly the same thoughts on RDRAM vs. SDRAM.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
March 6, 2002 4:48:42 PM

It sounds cool Silver, but I think we'll see this optical-interconnect happen at the chip level before we see it on mobos. Then again, maybe I'm wrong.

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
March 6, 2002 5:56:26 PM

It's a hard call to make either way.

I mean I've already seen optical SCSI in use, so in theory a motherboard could already be developed in this manner. A CPU on the other hand is still not prepared to be optical.

Yet at the same time, such a solution would be costly and might not even give any noticable improvement. (At least not for those who refuse to overclock.) While it would grant future compatability with virtually any bus speed that a CPU, or memory (among other things) could ever reach, that isn't something that motherboard manufacturers have ever really cared about.

So it could theoretically be done already, but in reality probably never will, or at least not for quite some time. Which is a shame, as it could also significantly improve signal noise stability problems.

<pre><font color=green>//error-proof coding</font color=green>
<font color=blue>void</font color=blue> main(){<font color=blue>return</font color=blue>;}</pre><p>
Anonymous
a b } Memory
March 7, 2002 6:19:51 AM

let's just face the facts here people. what it comes down to is this: some people want Rambus to die a horrible, painful death. other people don't. it's just the way things are - it's the effect that Rambus has on people.

i want Rambus to die a horrible, painful death. we will see in a couple years whether this happens or not. no amount of speculating and posturing on paper will determine the success or failure of RDRAM - it will be the market that ultimately decides.
March 7, 2002 1:49:13 PM

Heh heh. I want Rambus to die a horrible, painful death. However, I want some other company (or open standards organization) to pick up the rights to RDRAM. Maybe then someone will finally push a number of evolutionary steps into it to really let it perform.

<pre><font color=green>//error-proof coding</font color=green>
<font color=blue>void</font color=blue> main(){<font color=blue>return</font color=blue>;}</pre><p>
March 7, 2002 3:41:26 PM

I will just stipulate this first before I state anything else. I do not want to be argumentative, nor do I wish to sound like a jerk. I have nothing personally against you nor did I slam you in my last comment nor will I here.

<b>A.</b>

DDR 166 or PC2700 does not run at 333MHz and DDR 133 or PC2100 does not run at 266MHz. The clock speeds are 400/3 or 133 1/3 MHz and 500/3 MHz or 166 2/3 MHz. (Like you stated. I never intended to be that precise. Thought that 166MHz would have sufficed. Even Fatburger did not slam me for that, in which he in my opinion is the Slam-King. Three cheers for FB!)

Look at the white sheets from the vendor of your choice.

1. <A HREF="http://download.micron.com/pdf/datasheets/modules/dd8c1..." target="_new">Micron Inc.</A>.
2. <A HREF="http://www.samsungelectronics.com/semiconductors/DRAM/D...(08_16)38d.htm" target="_new">Samsung Electronics</A>
3. <A HREF="http://www.mushkin.com/cgi-bin/Mushkin.filereader?3c878..." target="_new">Muskin</A>


See <A HREF="http://www.corsairmicro.com/main/tsdramfaq.html#whats_d..." target="_new">here</A> for an explanation of DDR SDRAM. In simplified words it means that two signals are carried on one wave hence giving Double Data Rates but the signal speed or clock speed remains the same. DDR 266 is PC133 with a doubled data capacitance on the wave and is not a single data signal at double the speed.

I don’t know have to explain this more clearly. I had hoped that I was clear on the previous post but I was mistaken.

<b>B.</b>

As for the Gbs vs GBs. I had a slip of the shift key. It can happen to anyone. (As Doug McKenzie once said, "It wasn't me, eh? It was the chair.")

<b>C.</b>

As for actual vs. theoretical; I don’t put a lot of faith in only using <A HREF="http://www.sisoftware.demon.co.uk/sandra/index.htm" target="_new">Sisoftware Sandra</A> or any single benchmark. (I like looking at different benchmarks and concluding what the “real world” results are for myself.) Using only one does not give an accurate picture of throughput for a memory system. I like the article over at <A HREF="http://www.aceshardware.com/read.jsp?id=45000279" target="_new">Ace’s Hardware</A> which has a display of average bandwidth in MB/s. (Ace utilized these figures using STREAM and Cachmen.) When looking at these you will notice that the Asus KT266A board is showing only 784MBs/s of the available 2666.667MBs/s. That would be less than 1/3 of the theoretical. The Asus i845D only averaged 1016MBs/s. That is a little better than 1/3 of the total available theoretical bandwidth. The PC800 on the Asus board with i850 had a throughput utilization of over 80%. So when I stated that RDRAM has a better efficiency in “actual throughput,” this is where I derived the conclusion for my statement.

I hope that this clarifies what I was trying to state previously.

<b>"Kenny! Give me the whoobie."

"220... 221. Whatever it takes."

"You don't feed a baby chile!" - Mr. Mom</b> :lol: 
March 7, 2002 4:17:11 PM

Where can I download Stream and Cachemem?

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
March 7, 2002 7:29:38 PM

<A HREF="http://www.streambench.org/" target="_new">Stream</A>

and...

<A HREF="http://www.outertech.com/downloads.php?product=3&PHPSES..." target="_new">Cachemem 5.11</A>

BTW: FB did you get HL or CS yet? I forgot to mention that I am getting all four my wisdom teeth removed tomorrow at 9:00AM EST. (Does this mean that I am going to get dumber? Oops! Too late!) So on Saturday I will be trying to kill everything in sight. I am determined to game on Saturday and I will take it out on my friends and anyone in my sights.

<b>"Kenny! Give me the whoobie."

"You don't feed a baby chile!" - Mr. Mom</b> :lol: 
March 7, 2002 9:03:01 PM

Quote:
I do not want to be argumentative

Nor I. Education is my primary goal - of myself and others.

Quote:
DDR 166 or PC2700 does not run at 333MHz and DDR 133 or PC2100 does not run at 266MHz. The clock speeds are 400/3 or 133 1/3 MHz and 500/3 MHz or 166 2/3 MHz. (Like you stated. I never intended to be that precise. Thought that 166MHz would have sufficed. Even Fatburger did not slam me for that, in which he in my opinion is the Slam-King. Three cheers for FB!)

While you are technically correct on the fact that DDR effective speeds are not actual cycle speeds, they are in actuallity, specified in MHz. Look at your own muskin link it states "PC2700=333MHz FSB." This is simply common usage. People commonly refer to the AXP's FSB as 266MHz when it is in fact clocked at 133MHz with DDR technology. The same is true of PC800 RDRAM (400Mhz DDR) and P4's 400MHz FSB (100MHz QDR).

In addition, while some "purists" would like us to refer to PC2100 and PC2700 modules as DDR133/PC266 and DDR166/PC333, the DDRxxx rating refers not to the MHz clock rate of the module, but to the data bandwidth of the RAM chips in Mb/s/pin. So, in effect, your usage of the terms "DDR 133" and "DDR 166" are incorrect. It just so happens that DDR333 (333Mb/s/pin) chips run at 166MHz (333MHz effective). DDR333 chips are placed in sets of eight (non ecc/parity) on PC2700 modules to achieve 2666MB/s (333Mb/s * 8bytes).

The memory manufacturers decided to modify the original rating of DDR200 chip base PC200 modules to PC1600 to combat Rambus' rating of PC800 RDRAM. This is a political issue and the reason why I generally use both the chip rating (DDRxxx) interchangeably with the module rating (PCxxxx) when referring to DDR SDRAM.

Quote:
As for actual vs. theoretical; I don’t put a lot of faith in only using Sisoftware Sandra or any single benchmark...

...I like the article over at Ace’s Hardware which has a display of average bandwidth in MB/s. (Ace utilized these figures using STREAM and Cachmen.) When looking at these you will notice that the Asus KT266A board is showing only 784MBs/s of the available 2666.667MBs/s.

I usually don't either, but in this case, we were talking about the capablities of the RAM modules themselves and their efficiency in conjunction with the rest of the system. While artificial, Sandra 2002 seems to perform this measurement better than any other. As has always been my arguement, the software, chipset and the rest of the system can cause bottlenecks. This is why I would like to see truely equivalent DDR/RDRAM platforms for the P4.

Look at your <A HREF="http://www.aceshardware.com/read.jsp?id=45000279" target="_new">Ace Hardware</A> figures again - both the PX4266 and i845D PC2100 based chipsets offer 2133MB/s bandwidth and the dual-channel i850 PC800 based chipset offers 3200MB/s.

DDR SDRAM:
Tyan P4X266 PC2100 did 1020/2100MB/s = 49%
ASUS i845D PC2100 did 1016/2100MB/s = 48%

RDRAM:
ASUS i850 PC800 did 1320/3200MB/s = 41%
ASUS i850 PC1066 did 1741/4266MB/s = 41%


It would still seem that DDR is more efficient than RDRAM on P4 platforms - even when they run asynchronously to the FSB which gives them a significant disadvantage.

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
March 7, 2002 9:29:02 PM

Thanks, I've been trying to find the latest versions.

Halflife and CS came with my Radeon 8500, and since I only ship them the card (not the whole package) for RMA, I'll install them and see how I like it.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
March 8, 2002 12:18:55 PM

Wow. People are still enjoying HL?

<pre><font color=green>//error-proof coding</font color=green>
<font color=blue>void</font color=blue> main(){<font color=blue>return</font color=blue>;}</pre><p>
March 8, 2002 4:28:52 PM

Apparently. And, amazingly enough, there are still people who haven't played it :lol: 

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
March 11, 2002 3:59:24 PM

Maybe there is more value to it in online use or something. [shrug]

<pre><font color=green>//error-proof coding</font color=green>
<font color=blue>void</font color=blue> main(){<font color=blue>return</font color=blue>;}</pre><p>
March 12, 2002 4:42:56 PM

There are still around 2100 - 3000 servers up at all times. If you average at a minimum of 10 people per server that is 210,000 to 300,000 people online killing each other in HL or a mod.

FB,

Send me any copies that you don't want. PM me for my address. hehe... the sad thing is that I am not joking.

<b>"Kenny! Give me the whoobie."

"You don't feed a baby chile!" - Mr. Mom</b> :lol: 
March 12, 2002 5:53:06 PM

[shrug] Just from a single-player perspective, HL was kind of a let down. Especially the final boss fight. The OF mod was kind of fun, but too short. At least it had a better boss fight. I haven't tried any of the other mods. Can you make strong points for any of them? I might try another if it's any good.

As far as multi-player goes, I haven't bothered. The concept has never really interested me, especially since only recently has my connection speed gone up from a 26.4 modem connection. (Bad phone lines in my old apartment.) Even still, my new ISP has such a poor bandwidth to the internet itself that even though I can connect at 43.3, I can only download at a quarter of that at best. And most of the time I can't even connect to my ISP past 28.8 anyway.

I hate ISPs.

<pre>If you let others think for you, you're the
only one to blame when things go wrong.</pre><p>
March 12, 2002 5:53:06 PM

Copies of the stuff that came with my card, you mean? I'll keep that, I'm sure.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
March 13, 2002 4:47:57 PM

If you don't want them...

Why let them go to waste?

I am trying to have a mini-LAN party once a month. This could help our efforts in converting people to play PC games. Buffalo is kinda backwards when it comes to IT. There are companies that are at the forefront and there are others that are still running DOS based Windows applications. Yes it is sad. Up until one year ago the largest bank in the area was using Windows 3.0, 3.1, 95, 98, 98SE, NT, 2000, ATM, and a whole slew of others on the same network. What a mess....

<b>"Kenny! Give me the whoobie."

"You don't feed a baby chile!" - Mr. Mom</b> :lol: 
!