DDR Dual vs, RDRAM Dual

Okay I'm not quite sure if everything is right but is RDRAM still more superior than DDR Dual (when it comes out in the future)?

Looking now in the next few weeks or month PC1200 32-bit RDRAM will be out at 533MHz with a bandwidth of 9.6 GB/s.

Now future and I'm not sure when but PC4200 2x32-bit DDR RAM will be out with an clock rate at 266MHz if I'm correct and correct me if I'm not...

so it's going to be:
PC4200 DDR533 Dual 266MHz 2x64-bit 8.4GB/s bandwidth
PC1066 RDRAM Dual 600Mhz 2x32-bit 9.6GB/s bandwidth

The only difference I see is that DDR RAM has a 64-bit data bus but everything else RDRAM seems far more superior...

So can anyone please explain which one is better?

38 answers Last reply
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  1. Do you have links saying PC1200 is coming any soon? I hardly beleive so, it won't be out any soon, if PC1066 isn't yet.

    Yes DDR Dual would do only but benefit for P4. It would provide with DDR333, 5.4GB/sec, and with DDR400, 6.4GB. The latency SHOULD be lower, but I am not sure. However seeing as DDR's latency is what allows it to compete RDRAM P4 system benchmarks, I am only guessing that Dual DDR would boost it above it in bandwidth and latency which was already an advantage.

    Thunderbirds in wintertime, Northwoods in summertime! :lol:
  2. Nope sorry. I'm saying FUTURE.. I think PC1066 is out because at Asus:

    their mobo specs. tell you to use the following RDRAM:
    Vendor Type Size Model
    Samsung 1066-35 128MB MR16R0828BN1-CM9

    okay DDR400 at 6.4GB/s
    what bout PC1066 RDRAM at 8.4GB/s?
    and DDR only has 200MHz clock rate compared to RDRAM at 533MHz..

    so is this all coming down to the latency?
  3. It's been 1 year that PC 1066 is availble for benchmark and PC 1200 it now avaible and PC1600 it on Samsung roadmap

    cheap, cheap. Think cheap, and you'll always be cheap.AMD version of semi conducteur industrie
  4. DDR is currently using effectively 266FSB (133 double pumped). The difference between DDR and RDRAM FSB speeds will only really matter if you want a P4 paired with DDR. This is because the P4 needs the extra bandwidth more than an AMD system.

    The ommission of P4's using DDR really bugged me about the review, for the reason above. Since the majority of P4 systems are shipping with DDR, I wanted to see how much performance was lost. I'd like to see what happens to that 2.4 or 2.5GHz P4 when it's using DDR, compared to the XPs.
  5. So really if you are going with a P4 you are better off with RDRAM due to its bandwidth?..

    Well really how does FSB work? Sending data between the cpu and mobo?... Doesn't this provide more speed?
  6. Cas2 DDR333 has about equal performance to PC800, do to it's lower latency. For a 133MHz FSB, PC1066 or overclocked PC800 should therefore be roughly equal to Cas2 DDR444. But since DDR of such capability is at least months off, the best solution right now is RDRAM.

    Dual Channel DDR will have the best of both worlds, low latency and high bandwidth, and should supplant earlier technologies.

    What's the frequency, Kenneth?
  7. Hmm I highly disagree your claim of DDR444 CAS2 would equal PC1066.
    It is very very unusual if it did. DDR400 just lacks CAS2, and proper chipsets, as well as FSB. At 200MHZ FSB P4s, and DDR400 chipsets and RAM, at CAS2, the thing will more than likely rival PC1200 for a while, until DDR444 ever comes out. Of course then the Dual DDR will be out, therefore it'll be almost useless to get RDRAM unless the solution provides disappointing results.

    Thunderbirds in wintertime, Northwoods in summertime! :lol:
  8. dont forget though that in due time the hammer will come out, and it will support dual DDR :)

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  9. I'm just using DDR333 vs PC800 as the basis of comparison, divide 1066 by 800 then multiply by 333 and you get 444.

    What's the frequency, Kenneth?
  10. Ok so what is the new RDRAM really up against in the future?
    Right now it's the best but future dual DDR will be out and how will it be better than RDRAM?
    Would a P4 still be better off with RDRAM as it's already dual or better with dual DDR Ram?

    Or is dual DDR only going to be good with AMD?

    I'm basically trying to figure out which one to buy as is it better just getting PC1066 RDRAM and not worry bout changing the mobo or ram anymore or should I wait for dual DDR and use that instead?
  11. Dual DDR will do NOTHING for AMD!!! It is NEEDED for making DDR memory bandwidth match RDRAM bandwidth for the P4. RDRAM has a latency disadvantage, DDR has a bandwidth disadvantage, when DDR is used in Dual Channel for the P4 there will be no reason for RDRAM any longer.
    DDR speed should NEVER catch up with RDRAM, RDRAM will probably be extinct before then. But DDR won't NEED that kind of speed if you double it's bandwidth through the use of Dual Channel bus.

    What's the frequency, Kenneth?
  12. Crashman, why do you keep saying 444MHz DDR is impossible? Grab some Samsung, Corsair or KingMax PC3200 and you'll overclock it to 225MHz (450MHz DDR) in no time with slight overvolting. The ratio for the memory is 4:6 (FSB:Memory) when running on a 133MHz FSB. Overclock the FSB to 150MHz (which most RDRAM can't handle at PC1200), up the voltage a bit on some good Samsung DDR RAM, and you'll be running the DDR RAM at 450MHz. 150*6/4=225MHz*2 = 450MHz.

    You'll have a P4 2.4GHz, and 450MHz DDR RAM.

    :wink: <b><i>"A penny saved is a penny earned!"</i></b> :wink:
  13. It's impossible at Cas2 is what I'm saying. It needs to be at Cas2 to beet PC1066.

    What's the frequency, Kenneth?
  14. Quote:


    Agh! Why do you always write beet instead of beat?

    Anyway, No, you don't. PC2700 CL2 OUTPERFORMS PC800. CL2.5 should match it, give or take.

    :wink: <b><i>"A penny saved is a penny earned!"</i></b> :wink:
  15. And warrantee instead of warranty. I think Crash just likes dual letters :lol:

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  16. Ok I'm getting somewhere now.. So what is the most important factor?? Latency or bandwidth?
    okay when dual comes out, let's say DDR400 Dual that would be 6.4GB/s of bandwidth compared to Dual PC1066 32-bit RDRAM at 8.4GB/s....

    Any idea when dual ddr will be out?
    and if your single DDR modules will be compatable with the dual ddr configuration?
  17. Latency seems more important with a AMD system.
    Bandwidth is by far the most important thing with a P4 system.

    Today on Toms: Trisexual hamsters, anal applications of peanut butter and Marrage councilling!
  18. okay then looking just at my last post isn't P4 better off with RDRAM still then as it would still lead with an extra 2 gigs??..

    Another question out of this subject but may be answered easily is that what's the difference with P4 cpus that have an "A" or without an "A"? was it just the extra 256k of cache?
  19. well one would assume that the dual channel rdram would be beter, but its sheer speculation when we would expect to see it.

    the P4 A is very different from the 'non A'

    die shrunk from 0.18u to 0.13u
    core voltage correspondingly lower 1.75 to 1.5
    die size is also smaller
    cache has been doubled
    and cauz of the die shrink it overclocks a hell of alot better and rins significantly cooler.

    Today on Toms: Trisexual hamsters, anal applications of peanut butter and Marrage councilling!
  20. okay. So there's not really a precise answer if dual ddr ram will be better than dual rdram until it's out and be able to actually compare in benchmarks?...
    I'm looking for the best ram in a P4 system but not sure if I should buy RDRam or wait until DDR comes out..

    ah thanks for the info. on the P4 'A' cpu.. so basically the 'A' was put on for the 1.6-1.8GHz cpus as there were regular 1.6 and 1.8 cpus that had half the cache and the die was still 0.18u right?

    Well if they overclock a whole lot better than any new P4 2.0GHz Northwood would be able to overclock just as well as the P4 'A' cpu's right?

    This doesn't relate to the above but a general question.. Is it possible to run an o/s on a slave hardrive when there is another o/s on the primary hardrive? I couldn't figure out how it's possible as when a computer loads up it starts from the Primary IDE channel... but I heard it is but I couldn't figure out how it would work to picking which one to load...
  21. if u want the absolute best, just go the p4 with rdram and overclock to PC1066 speeds.

    and no.
    the 0.18micron P4, the 'willy' was released in speeds ranging from 1.3ghz to 2.0ghz.

    when the 0.13 die shrink 'northwood' was released the main speeds were 2.0, 2.2 and 2.4, but some were also released at the slower speeds of 1.6 and 1.8, most likely to fill the gaps due to the end of production of the 'willy'.
    these 1.6A and 1.8A cpu's are essentially faster ones that have been downgraded with a lower clock multiplier, thus the reason why they overclock so damn well!

    Today on Toms: Trisexual hamsters, anal applications of peanut butter and Marrage councilling!
  22. so overclock PC800 to PC1066?? Is that really possible? what about with air cooling? or would it be better to wait for another few weeks and wait for PC1066 RDRAM....

    ah I see...
    So basically the 1.6A and 1.8A will overclock better than a regular 2.0 or 2.2 or so on?....
  23. yes it can. specifically sambsung RDRAM.
    and yes 1.6A's and 1.8A's overclock extreemly well.

    Today on Toms: Trisexual hamsters, anal applications of peanut butter and Marrage councilling!
  24. okay this

    all this means I don't have to buy the new mobo that supports PC1066 when I can just use the older one that supports PC800 and overclock to PC1066 RDRAM without any problems if I buy Samsung RDRAM?..

    so the 1.8A would overclock better than regular Northwood processors? I can determine which one to buy as to overclock.. It would be either a 2.0 or 2.2 or a 1.8A... I'm using aircooling but I'm not sure which one I'm better off with...
  25. think so yeah
    but its best going to the cpu overclocking forum and asking someone like fatburger about what he did

    Today on Toms: Trisexual hamsters, anal applications of peanut butter and Marrage councilling!
  26. alright then.

    would it even be worthwhile to buy PC1066 RDRAM when it becomes available and cheaper?..
    I mean wouldn't PC800 RDRAM will be more than enough already? or does it stil limit a P4 performance greatly?..
  27. sure. whynot?

    i bet u will be able to overclock pc1066 even higher, and as all the benchmarks show the P4 thrives of memory bandwidth... the more the merrier.

    Today on Toms: Trisexual hamsters, anal applications of peanut butter and Marrage councilling!
  28. alright but lets say you had PC1066 RDRAM..
    would you see a significant difference than PC800 RDRAM?..
    or would you only see minor improvements and not doing much than PC800 RDRAM?

    Yes P4 thrives for memory bandwidth but is it ever possible to use all of that bandwidth constantly?..
    Like even 6.4GB/s of bandwidth.. how would you use all of that all the time?
  29. well yes. a 33% performance boost
    provided you are also using the 533 bus speed.
    thus people overclock from 400fsb to 533 with 1.6A's and 1.8A's.

    use all of it?
    probably. the P4 is less efficient than the athlon in using it. or to be precise needs it more to keep the p4 architecture satisfied with data.

    something like divx encoding would pretty much max it out.

    Today on Toms: Trisexual hamsters, anal applications of peanut butter and Marrage councilling!
  30. As an interesting sidenote, a P4 with PC2100 DDR is faster than an RDRAM system is some business benchmarks, and 3D benchmarks, where latency is more important than bandwidth but in video encoding/decoding, it would be significiantly slower. So again, depending on what you do, one RAM will be faster than the other.

    :wink: <b><i>"A penny saved is a penny earned!"</i></b> :wink:
  31. hmmm interesting.

    i think on the whole though for the P4 bandwidth wins 90% of the time.

    if I had a P4 i would use RDRAM...

    on another interesting note, ive just purchaced PC3200 ram *grins*
    time for a midlife upgrade for my t-bird.

    Today on Toms: Trisexual hamsters, anal applications of peanut butter and Marrage councilling!
  32. Get yourself an Iwill XP333 or an EPoX 8K3A+ and overclock that thing like mad.

    :wink: <b><i>"A penny saved is a penny earned!"</i></b> :wink:
  33. ...which will also fry by another electrical cutout, or your hamster again biting the lines!

    I set my graphics aperture to 1024MB, why can't I open anything now? :mad:
  34. Okay so everything is like overclockable..

    well okay besides encoding?..
    There aren't really too many things that can max it out that easy? unless your the video editing type of person...

    Crashman was say any P4 with 512k of cache is a normal Northwood processor.. So aren't these 1.6A and 1.8A's also normal Northwood Processors?...
  35. well i bet 3d games also fit. lots of calculation going on on physics and objects.

    i know that UD cure for cancer is reasonably bandwidth demanding too.

    course the 1.6A and 1.8A are normal northwoods. they are just clocked lower to fill the gaps in intels product line.

    Today on Toms: Trisexual hamsters, anal applications of peanut butter and Marrage councilling!

    gonna run at 166 for the 1/5 divider for complete PCI/AGP happyness and off a UPS so things dont get fried QUITE so often.

    Today on Toms: Trisexual hamsters, anal applications of peanut butter and Marrage councilling!
  37. Gotta love UPS'...
    Why aren't the surge protectors doing their thing then? Maybe they fear the hamster who glares at them continuously!

    I set my graphics aperture to 1024MB, why can't I open anything now? :mad:
  38. ah.. There's too much to get top performance!
    I think technology is expanding to damn fast!
    When you want something new something new already comes out.... But I believe that not everyone would really need or want a top system if they can't use the full potential of it...
    I think a 2.0GHz and 512MB or 1GB of PC800 will be more than enough as I will probably overclock it all..

    If 1.6A and 1.8A are regular northwoods I might as well just get 2.0GHz and have a little higher clock rates..

    Anyways thx for the tips!
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