1GB DDR DIMMs began appearing in the market over a year ago. Since that time, one of the most - asked questions from our readers is whether they should buy 512MB or 1GB DIMMs.

The answer to that question has not been easy up to now. On the one hand, two 1GB DIMMs on the AMD Athlon 64 could still run at 1T Command rate, instead of the 2T required by the 4x512MB DIMMs needed for 2GB with 512MB DIMMs - a definite advantage for the 1GB DIMMs. On the other hand, the available 1GB DIMMs were generally much slower than the fast 2-2-2 DIMMs that were commonly available in 512MB DIMMs. We normally saw 3-3-3 or 3-4-4 or slower timings for 1GB DIMMs. These poorer timings for 1GB DIMMs took away most of the advantage for the 1GB 1T Command Rate.

There was an additional "gotcha" with the 1GB DIMMs that many enthusiasts quickly discovered. With a starting point of 3-3-3 or 3-4-4, the 1GB parts did not overclock nearly as far as the 512MB parts. For all of these reasons, we had generally recommended that most users were better off with 512MB DIMMs - at least until memory timings improved on the 1GB DIMMs.

The time for faster 1GB DIMMs has finally come, and they are starting to appear from many recognized and a few new manufacturers. Since there were so many questions about whether the 1GB DIMMs were a wise choice for Athlon 64 buyers, we looked at three very different 1GB parts supplied as a 2GB kit - or 2 1GB DIMMs. These are the Corsair CMX1024-3500LL PRO (DDR433), Gigaram 2GB Dual Channel PC-4200 (DDR533), and OCZ PC4000 1024MB EB Platinum (DDR500).

 Manufacturer  Description
(Memory Chips)
 Memory Speed  Rated Timings  Voltage
Corsair CMX1024-3500LL PRO
(Infineon)
433DDR 2-3-2-8 2.6V
Gigaram 2GB Dual Channel PC-4200
(Infineon)
533DDR 3-4-3-8 2.9-3.0V
OCZ PC4000 1024MB EB Platinum
(Probably Infineon)
500DDR 3-3-2-8 2.6V

Our memory tests differentiate memory in two ways. First, AnandTech has always been an advocate of real world performance measurements, and we've shunned using just synthetic benchmarks in our testing of every type of component, including memory. This is not because synthetic benchmarks are not useful - they are often very revealing of component differences. It is because running just synthetic benchmarks can severely distort the picture of performance with real applications and real games. That is why we always use games and the pure number-crunching Super Pi in our memory tests. It is also the reason why we test using both Buffered (Standard) and Unbuffered synthetic benchmarks. We have found in much of our testing that the less commonly used Unbuffered benchmarks more closely mirror how games really respond to memory differences.

Second, we moved to testing different memory speeds at the same CPU clock speed in our Athlon 64 memory tests. The AMD CPU, with unlocked multipliers, allowed us to finally remove the CPU speed differences from our memory tests. This allows you to see the true impact of memory speed increases and memory timings on performance. As you have seen in past reviews, those performance differences are very real, although they are much smaller than many memory manufacturers might want you to believe. On the other hand, faster memory speeds and faster memory timings do improve performance, no matter what some nay-sayers are determined to prove.

Using these tests, we expected that the wide range of specifications for these 1GB DIMMs would allow us to differentiate which type of specification would best fit certain end users' needs, and easily pick a winner. Along the way, however, we found that things are not always as they appear, and this is particularly true in the high-end memory market.

Why 1GB DIMMs?
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  • woodspire - Thursday, June 29, 2006 - link

    What happen if instead of using 4x 512 memory you use 2 x 512 and 2 x 1024. Same speed (PC-3200), same timing, and even same brand.

    Still acheving dual channel ?
  • qquizz - Saturday, December 10, 2005 - link

    Sounds great and all but a query at Pricewatch brought up a blank.
    Where can you buy the OCZ PC4000 EB Platinum Edition
  • Hurricanesan - Friday, November 11, 2005 - link

    I'm looking for 2Gb memories for my new computer.
    I had an hard time choosing between the Corsair 3500LLPro and the OCZ 1024MB EB Platinum.
    This morning, I've noticed this test. Since the OCZ was able to go up to 500Mhz and I plan using an A8N32-SLI, the choice looked easy.
    But a friend of mine pointed out an old story in which OCZ was giving very good sample to the press and lesser products in the shops. I've looked about that story and now it seems to me that OCZ is really unstable in its production and not very clean ... or used to be.

    I would really not like to buy those memories and find that they can't stand their specification.

    Since right now it seems that both the Corsair and the OCZ are not available in stores less that 2 hours plane from me, I have a week to make up my mind.

    If anyone can help me balance one way or the other, please post.

  • KriegsMaschine - Tuesday, November 29, 2005 - link

    OCZ is the best brand I'd say. I currently have Corsair Twinx C2Pro "2x512 ddr400 Cas 2.5" and it's good... but WAY TOO expensive for it's quality. You pay too much for the brand like you would by getting a cloth from a designer. OCZ have the best performance while having reasonable prices and quality stuff for Value, Mainstream and High-End. Their tech support is very good too, as all their products. My next PSU will be OCZ ModStream 450watts.

    Nice article. I was thinking these days about going from 2x512 to 4x512 with my Athlon64 since it's less expensive than 2x1Gb and generaly have better timing but after reading that 1T Command was impossible with 4 DIMMS... I changed idea!


    What would had been nice for the review would had been some more real game benchmarks. I mean not old stuff like Quake 3 because who care to have +20fps when you already got 550! Some newer stuff such as UT2003, FEAR, BF2, FarCry, HL2 would had been a better choice. To me those SuperPi, SandraMark... means almost nothing. All I want when getting such expensive rams is more FPS in games. Comparing 2x1Gb in 1T Command vs 2x1Gb in 2T Command would had been better too because don't you think 2x512Mb vs 2x1Gb is unfair? 0_o
  • Shimmishim - Wednesday, October 12, 2005 - link

    what the heck? no 2x1 crucial ballistix? wow. i have a set that can do 290 mhz 1:1 with 3-3-3-7 timings and only 2.8 volts.
  • leexgx - Saturday, November 5, 2005 - link

    do not think it was out then (or it was not sent to anandtech)

    i just got the Crucial 2GB DDR PC4000 Ballistix from overclockers and its less then £200 for this week only (norm £240) (got the A8N-SLI premium as well)

    i good to see that Ballistix stuff can do that

    i probley just set me X2 3800+ at 250 so me ram is doing the same (got it at 241 now on the cpu it norm runs at 200 so its an 410mhz oc {4600+ x2})
  • ricleo2 - Wednesday, October 12, 2005 - link

    After some recommendations from the forum here, I just got 2 sticks of GSKILL PC4000 at one gig apiece to replace my OCZ 2 sticks at 512 Megs apiece in my MSI K8N SLI PLATINUM. After comparing benchmarking results, before and after, it was not even close. RMA already approved from NEWEGG.
  • phidjit - Wednesday, October 12, 2005 - link

    It's 1024, with 2-3-2-5 timings and runs at DDR433, it seems like it would have been a better comparison to the Corsair "CMX1024-3500LL PRO" (also 1024, DDR443, but 2-3-2-6 timings).

    Anyone seen benchmarks for the gigaram mach10000?

    It looks like it could be a bargin.

    phidjit
  • qquizz - Wednesday, October 12, 2005 - link

    These are the type of articles I come to AT to get. Thanks Wes.
  • znir - Wednesday, October 12, 2005 - link

    Thanks for the information in the review. however, i think it would be good to see result of 4x512MB high performance sticks like the OCZ PC4000 VX.

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