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
433DDR 2-3-2-8 2.6V
Gigaram 2GB Dual Channel PC-4200
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?


View All Comments

  • Wesley Fink - Tuesday, October 11, 2005 - link

    The published "ram guy" link is the one printed on the Corsair retail package. We also tried the link and it connects to the Corsair Help Forums.

    If you have another link please list it in the Comments.
  • Madellga - Tuesday, October 11, 2005 - link

    I am using this OCZ kit (EL, not the one in the review) since August on a San Diego / DFI combo. It goes to 230@2.5-3-2 with 2.7V and 1T.

    I tried also 4 sticks (a friend bought it also) and we made to 220@2.5-3-2 with 2.7V and 2T.

    I didn't try above 230, as the OCZ Guy pointed the 230 to be the limit. I am using 180/200 or 166/200 to overclock the San Diego, leaving the memory between 220-230.

    It is rock solid, it can Prime all night without mistakes.

    I prefer to have more memory even if a bit slower - it is much worse to have Windows writting to the swap file.
  • ElFenix - Tuesday, October 11, 2005 - link

    just to see how much the difference is when going from 1 gig to 2 gigs Reply
  • Wesley Fink - Tuesday, October 11, 2005 - link

    We tested many applications with 1GB vs. 2GB of ram. BF2 greatly benefited, but nothing else we've tested so far really improved much with 2GB. That will likely change with the release of newer, more demanding apps and games that take advantage of the new dual-core processors.

    One High-Performance memory company told us that after they saw what 2GB did for BF2 they ran 1 vs 2 on every game they could get their hands on. The goal was to publish benchmarks to show the advantage of buyers using 2GB instead of 1GB - and sell more memory. They privately told us they also found no real performance improvement in anything other than BF2.

    We do expect 2GB/4GB will make a difference in multithreaded and true 64-bit apps in the future. Of course multi-tasking also normally benefits from more memory.
  • Johnmcl7 - Wednesday, October 12, 2005 - link

    The only other game I've seen people recommending 2GB for is the FEAR demo but of course it's not final yet.

    Good read though, I thought the discussion on the A64 and the various ram issues was particiularly useful.

  • Margalus - Wednesday, October 12, 2005 - link

    2Gb make a good difference in WoW also. Reply
  • Vesperan - Wednesday, October 12, 2005 - link

    the memory combinations on the 'Why 1GB Dimms?' page could be shown as a 2x2 matrix (with 2/4 dimms on one axis and 1T/2T on other). Performance at each combination could be shown - except of course for 4 dimms at 1T. Currently the article contrasts the 2 dimms and 1T combination with 4 dimms and 2T, could it be possible for you to add 2 dimms at 2T?

    I would just like see the effect of 1T to 2T, or 2 dimms to 4 dimms ceterus paribus - that is, all else being equal. While I dont think the missing combination (2 dimms at 2T) will undermine your arguments made, I would like to see how it fits into the overall picture.
  • Phantronius - Tuesday, October 11, 2005 - link

    I did, BF2 runs so much better as a result Reply
  • Phantronius - Tuesday, October 11, 2005 - link

    1st!!! Honestly, since i've given up overclocking, I threw in 2 1gig Platnium Corsair XMS modules in my new Athlon 64 setup and it works fine and stable, couldn't give a shit if my "timings" are as *looot* as they could be. Reply
  • DigitalFreak - Tuesday, October 11, 2005 - link

    Well good for you Reply

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