Final Words

Corsair XMS4400 and OCZ PC4400 both perform as specified at their rated speed of DDR550. This makes these the highest rated memory that we have tested at AnandTech. Both also equal old records or reach new highs in memory speed at DDR560 to DDR571. While the OCZ reaches further than Corsair's DDR550, performance across the curve is very similar and the memory performance is, in most cases, so close that it is hard to choose one over the other. In Quake 3, though, OCZ PC4400 managed to set a new performance record.

It should also be mentioned that both memories were exceptionally stable to about DDR533-540, but neither were particularly outstanding in stability at the highest speeds. It was also interesting that the gains above DDR533 were pretty small. This could have been the fault of other system components, but since all testing was done on the recommended Asus P4C800-E, there is no place left to go. We do believe that the 10,000 RPM SATA RAID may be compromising stability at some of the highest memory speeds despite the PCI/AGP lock on Intel's current chipsets.

While it's true that these two DDR550 memories reach new high speeds in our performance tests, it is not to say that they are the fastest memory we have tested. Performance is much more than a speed setting and the lower timings required to reach these higher speeds took their toll on performance. Compared to OCZ 4200EL and Corsair XMS4000 PRO, the performance at the same speed was slower with the timings required for DDR550. At the other end of the scale, we also saw slower DDR423 with 2-2-2-6 timings meet or best DDR533 performance with the slower timings required for DDR550.

The fastest memory that we have tested thus far is the truly excellent OCZ 4200EL. It remains #1 in most of our benchmarks, and it is still the best high-speed memory that we have tested. Corsair XMS4000 PRO and Mushkin 4000 High Performance perform just as well as OCZ 4200EL, but their range is not quite as wide as the incredible DDR400 to DDR560 that we found with OCZ4200EL. If we were in the market for high-speed memory, we would choose one of these 3 memories over either Corsair XMS4400 or OCZ PC4400.

In the end, Corsair XMS4400 exceeded its specifications and performs very well at DDR550, which is an incredible bus speed of 1100MHz or 1.1GHz. OCZ PC4400 performed about the same throughout the range, but reached an even higher maximum overclock. Both of these DDR550 memories perform as promised. However, the fastest high-speed memory overall is still OCZ 4200EL, with Corsair XMS4200 PRO and Mushkin 4000 High Performance very close in performance.

We all want DDR500 that can run at 2-2-2-6 timings, but until that becomes a reality, memory like OCZ 4200EL, Corsair XMS4000 PRO, and Mushkin 4000 High Performance provide excellent speed and decent timings. If top-speed at any cost is your goal, then XMS4400 or OCS PC4400 will let you reach new highs in memory speed at voltages that won't fry your board.

After the reach to new highs, it seems all the companies that specialize in memory for the Computer Enthusiast have recently announced faster DDR400 memory. Considering how well very fast DDR400-433 performs compared to high-speed memory at slower timings, we understand why this is a hot topic again. Our next look at memory will examine performance of some of the latest, faster DDR400.

Highest Memory Speed Results
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  • klah - Saturday, August 14, 2004 - link

    good article
  • Pumpkinierre - Friday, February 20, 2004 - link

    #9 Perhaps you're right but all the reviews I read on the IC7 associated the game accelerator with PAT eg

    http://www.lostcircuits.com/motherboard/abit_ic7/6...

    the speed increase is of the same order as PAT ie 2-5% eg:

    http://www.xbitlabs.com/articles/mainboards/displa...

    But I acknowledge I made an assumption so could be wrong.

    #11 I get a ~1% increase in performance on 3Dmark2001 and 3dmark2003 (default settings benchmark and catalyst 9800pro drivers) when runnung P42.6c@3.2 at mem. 5:4 2237 (OCZ 2x256Mb PC3200 platinum original SS) Game Accel.-auto. compared to 2.8 1:1 mem. oçlocked 2237@216MHz GA-F1(memory wont handle Street Racer). In general game play, the 1:1 feels smoother in my opinion.
  • TrogdorJW - Friday, February 20, 2004 - link

    "Let me tell you , it does make a speed difference. Everything benches 1-3% higher."

    So it's a measurable difference, but not noticeable. :p

    I'd still like to see real benchmarks on a variety of applications rather than just take someone's unsubstantiated claim that 3.2 or 3.4 GHz with PAT is best. With the system bus OC that you get, I don't think buying a 3.2 would be faster than buying even a 2.8C and OC'ing to 3.2. However, I have neither so I have no way of knowing.
  • retrospooty - Friday, February 20, 2004 - link

    BTW , on my Epox 4pc3a+ I can enable, or disable PAT at any speed or ram ratio.

    Let me tell you , it does make a speed difference. Everything benches 1-3% higher
  • retrospooty - Friday, February 20, 2004 - link

    PAT works on i875 fulltime... Even at 5:4

    Those settings you are referrring to " F1 or street racer" are not actually PAT , that is GAT, its just Abit's memory tweaks. On the I865 Abit boards, GAT can enable PAT (much to Intels displeasure) but on I875 PAT is always enabled. the GAT settings are just memory tweaks.
  • Pumpkinierre - Friday, February 20, 2004 - link

    Turn it off and see if it makes any difference. On Abit you cant run F1 or street racer PAT settings above CAS2 or on 5:4. I dont know about Turbo but it doesnt add all that much anyway.
  • Icewind - Friday, February 20, 2004 - link

    Uhhh, you wanna bet? Im running PAT at 5:4 ratio with my Corsair 3700XMS on my P4C800-E Deluxe bud at 3-4-4-8.
  • Pumpkinierre - Friday, February 20, 2004 - link

    #4 and #5 you cant run PAT with 5:4 ratio nor with memory timed higher than CAS 2. So, Trog, your best cpu is a 3.2 or 3.4. That way you get the high speed with small overclock allowing the use of DDR433 low latency BH5 chipped memory (o'clocks to 450). Amongst the cheappies, the 2.8 is the best and use OCZ 466 gold which holds CAS2 up to 420 and then 2.5 through to DDR500. Or else use the 3500 Mushkin or OCZ low latency.

    #5 I dont see why you cant get 2225 at ddr500. Those graphics cards have got 2.2ns chips and run at DDR700-1000. I'm not sure about the latency but if you lower the speed you can improve on the latency. I'm waiting and I'll buy when it comes out. All these DDR533 and 550 seem to be a rehash of the same thing and missing the low latency quality that is required for PAT to be enabled.
  • Icewind - Thursday, February 19, 2004 - link

    Condsidering its the ASUS's highest end board, they probably left the PAT on, and why you would want it off in the first place is beyond me.

    Considering the limations of the current breed of DDR chips, a 2-2-2-5 or close to that at DDR500 simply isn't plausible from a manufacturing/cost point.

    DDR2 aint looking much better either, it runs at 4-4-4-12 settings stock. So I think the days of low timing memory are going to be going the way of the do do.
  • TrogdorJW - Thursday, February 19, 2004 - link

    I'd be curious to see a roundup of various benchmarks done with the varying memory speeds and timings, sort of like what you started with by comparing 3.2 GHz at 266 MHz bus to 3.2 GHz at 200 MHz bus. Here's what I'm thinking:

    Get a 2.4C, 2.6C, 2.8C, 3.0C, and 3.2C. (Or use your P4 3.2ES, I suppose.) Then do a variety of benchmarks (i.e. not just Quake 3, SuperPi and Sandra) at reasonable settings and memory timings.

    From what you've shown in this article, a 2.4C overclocked to 3.2 GHz will outperform a 3.2C at stock bus speeds. However, it could do this with low latency 5:4 ratio or higher latency 1:1 ratio settings. What appears to be the best choice? A 2.4C would require a 266 bus to reach 3.2 GHz, where a 2.6C would "only" require a 246 MHz bus, a 2.8C would require a 229 MHz bus, and a 3.0C would need a 213 MHz bus. At those bus speeds, the 2.4 and 2.6 overclocks would need to use either lower timings or a 5:4 ratio, but the 2.8 and 3.0 could probably get 2-2-2-6 (or 2-3-3-7 timings?) with a 1:1 ratio. Also, how does PAT affect things? Did you have it enabled on the 1:1 OC and not on the 5:4 OC? I wan't sure.

    I know, it's a lot of work and may not be that useful to many. Still, it's something I would enjoy seeing when/if you get the time. Anyway, with 2.4C, 2.6C, and 2.8C all costing about the same amount right now, I'm not really sure where the best buy is. 2.4C would probably be fastest if you could get really expensive RAM to handle the high OC and the processor worked at 3.2 GHz, but do 2.6C or 2.8C overclock higher on average, due to the higher multipliers?

    Great article, though. Nice to see that low timings can still match higher clock speeds. Also, any chance of seeing a similar roundup using Athlon XP? (I would also say Athlon 64, but they don't seem to have enough OC headroom.) Athlon XP might not be able to make use of anything over DDR533 - or maybe even DDR500 - but I haven't seen any good comparisons on it.

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