DDR CPUs ?

[Guest]

From the CPU articles I have managed to glean that in order to have a full 266MHz FSB DDR Athlon system you need

1. A DDR motherboard.
2. DDR memory.

What about the CPU ? Are we still waiting for DDR CPUs ? Or can I use an Athlon 'C', when they become available.. ?

Thanks

 

[jclw]

It is the chipset on the motherboard that provides the interface between the processor and the memory - you could make a DDR chipset for any processor. So to answer your question all you need is a motherboard with a DDR northbridge and the actual DDR memory.

 

[Guest]

You do not need any special CPU, only the DDR memory and DDR Mainboard. If you are not familiar with overclocking a Duron or Athlon CPU, than keep reading these posts. If you stick a 1Ghz Athlon in a DDR board, and that CPU was originally set to run on a 100mhz FSB, the the DDR Mainboard will try to run it at 1330mhz, which probably won't work. You will need to lower the multiplier in order to maintain a frequency in which the CPU will run, for instance 7.5 instead of 10. You can accomplish this with the L1 bridge trick, and then you can adjust the multiplier on the CPU without worry. The "C" models are going to be used in the DDR and PC133 systems, no difference. This is the only reason AMD is having to release a separate CPU, so the speed of the CPU can be maintained with the higher FSB.

 

[slvr_phoenix]

The real question is:

Does it count as overclocking if the chip speed stays the same?

- Sanity is purely based on point-of-view.

 

[Grizely1]

There is no such thing as a "DDR CPU". The CPU doesn't need to be special in order to use DDR sdram, just like P3 doesn't need to be special to use RDRAM.

All you need is a mobo with DDR support and preferably 266MHz FSB.

 

[Guest]

No it doesn't, if the CPU speed stays the same it is not overclocking, but you are running a higher FSB, which if you wish to look at this in a way as what the CPU originally was set at, than yes, it is overclocked in a way to give more performance, but not more total clock speed.

 

[Grizely1]

Hence the name over<b>clocking</b>. Getting more clock speed, not performance. (of course you get performance out of getting more clock speed but you know what I mean.)

 

[Guest]

just for arguments sake isn't the fsb "clocked" as well. so running the fsb at a higher frequency is overclocking. just what is that clock refering to?

 

[Grizely1]

I was thikning of that right after I post that thing.

 

[Crashman]

In spite of what Grisely says, ALL Athlons use a DDR system bus, which make the ideal for use with DDR memory, because the memory transfer rate can now be the same as the rate for the system bus. But the other part is true-it's all in the chipset.

Suicide is painless...........

 

[mpjesse]

You not overclocking the CPU- your overclocking the motherboard and memory more than anything (with a 133mhz FSB). Technically- the athlon is capable of extremely high FSB clock speeds- it's all dependant on the board and memory though. That's why you see people running around with 155mhz FSB's. The FSB has little to do with the processor in terms of capabilities. Why? The processor is pumping out data at speeds MUCH higher than 133mhz; the bottleneck lies in the north bridge and memory. Theoretically the FSB on any athlon CPU could be the same speed as the CPU- but again there's a bottleneck in the north bridge and memory. =)

Proof of this can be displayed in the Pentium 4. The Pentium 4 has enourmous bandwidth capabilities because is has a "400mhz bus" or the equivalent of it. Intel knew they could never get a north bridge to clock at 400mhz so they designed the bridge with 4 pipelines- each running at 100mhz right to the memory- which is a great idea. The problem with the P4 is the design of the actual CPU- it sucks.

I wouldn't be surprised if another chip maker adopts this sort of bus technology because it's extremely fast.

-MP Jesse

<P ID="edit"><FONT SIZE=-1><EM>Edited by mpjesse on 01/24/01 09:45 PM.</EM></FONT></P>

 

[phsstpok]

"Technically- the athlon is capable of extremely high FSB clock speeds- it's all dependant on the board and memory though"

If that's really true then why is an Athlon 'C' needed at all? I thought it was designed for a 133Mhz Front Side Bus because the old 100 Mhz version would be inadequate but if what you say is true no new processor is needed.

 

[Crashman]

Maybe the only difference is the multiplier, e.g 1000 can be 7.5x 133 or 10x 100. That's the only difference between Intels E and EB processors, so it would not surprize me if AMD did the same thing. I believe the only reason people have not pushed the bus speed on their athlons is that the VIA chipset could not, until now, handle it.

Suicide is painless...........

 

[mpjesse]

That's correct. No new processor is needed- IF you don't overclock. Currently the only way to overclock the FSB and get an athlon to use it is to unlock the L1 bridges. Basically you have to disable the clock lock on the athlon. Now, the reason AMD has came out with the athlon "C" is because you don't have to unlock the processor to get it to run at 133mhz. So, it basically a processor for manufactured systems and those who don't like overclocking. Get it?

-MP Jesse

 

[Guest]

Thanks Chaps ! (and Chappettes ?!)

I'm not really interested in overclocking, but if I can get an Athlon to work at 266MHz FSB with DDR memory then that's good news..

Cheers,

Blewyn

 

[tfbww]

I went to pricewatch to see if there was a price difference but I couldn't even find the "C" designator on the tbirds. Or is everything just C now, as it appears that many people have already said the bridge came closed?

 

[slvr_phoenix]

I looked for that very same thing a couple of days ago. And when I'd closely inspect the data on them, they'd always say 100 (or 200... since the double-pumping seems to confuse everyone) MHz FSB. Now, if it were the C, it SHOULD be 133MHZ (or 266MHz) FSB. But for the life of me, I couldn't find ANY on Pricewatch with that. Granted, I only spent maybe ten minutes looking ... but still, it shouldn't be THAT hard to find.

So my guess is that they exist, but no one is actually selling them? I don't know. But CNET (as if I ever trust them anyway) didn't have them either. So something seems kinda odd about that.

Also, from the Tom's Hardware Do-It-Yourself PC System hardware suggestions, I couldn't find that heat sink anywhere on Pricewatch. That concerned me a bit too. I mean what's the point of suggesting a system if you can't even buy all of the suggested parts? Heh heh.

- Sanity is purely based on point-of-view.

 

[Grizely1]

No doubt you never found anything. I don't think the C Tbird will be on the market in the next couple of days. Even weeks. Probably a couple of months is more like it.

 

[mpjesse]

I haven't seen any athlon "C's" for sale either. Overclocking a Athlon is like a joke. All you need to do is get a frigin pencil and scratch over 4 bridges. That's IT!!! Changing the voltage is a little trickier- but still not hard.

-MP Jesse