Searching for the Memory Holy Grail - Part 2
by Wesley Fink on August 26, 2003 11:11 PM EST- Posted in
- Memory
Memory Configuration (continued)
Our benchmarks in Part 1 were consistent with the configuration recommendations in the Intel White Papers for Memory Configuration of the 875 and 865 chipsets. We concluded with the following performance charts based on our testing and the information provided by Intel. We differ from the Intel White Paper charts only in the first and second positions for the Intel 865 chipset. When Intel published their White Papers, we doubt that they had any notion that most of the 865 motherboards being sold would have some version of PAT (Performance Acceleration Technology) on board. Our testing of the ASUS, AOpen, and DFI PAT-enabled boards shows that the PAT 865 boards behave more like 875 boards. We have confirmed that the first and second positions on PAT-enabled 865 boards are, as we report, below — with four DS DIMMs performing faster than two DS DIMMs.
| DDR400 (1:1) Performance | DIMM Configuration | Single-Channel or Dual-Channel |
| 1 | 4 DS | Dual Channel |
| 2 | 2 DS or 4 SS | Dual Channel |
| 3 | 2 SS | Dual Channel |
| 4 | 4 SS/DS Mixed Matched Pairs |
Dual Channel |
| 5 | Any DS | Single Channel |
| 6 | Any SS | Single Channel |
| DDR333/266 Performance | DIMM Configuration | Single-Channel or Dual-Channel |
| 1 | 2 DS or 4 SS | Dual Channel |
| 2 | 2 SS | Dual Channel |
| 3 | 4 DS | Dual Channel |
| 4 | 4 SS/DS Mixed Matched Pairs |
Dual Channel |
| 5 | Any 1 or 2 DS or SS (1 DIMM or 1 in each Channel) |
Single Channel |
| 6 | Any 1 SS | Single Channel |
While SiSoft Sandra UNBuffered Memory Test results demonstrated real differences in performance among these memory configurations, many of you asked what we might see in real-world performance differences with these different memory configurations.
Some of the configurations were easier to test than others. Kingston had provided us with four Single-Bank (single-sided) DDR500 DIMMs that allowed us to look at performance differences in two SS DIMMs versus four SS DIMMs. We looked at performance of 1000FSB/DDR500 at 3-4-4-7-1 memory timings at 2.65V.
| 1000FSB (3.0GHz)/DDR500 Performance — Kingston PC4000 2 x 256 MB SS DIMMs vs. 4 x 256 MB SS DIMMs |
||||
| Number of Single-Bank DIMMs | Quake3 fps |
Sandra UNBuffered | Sandra Standard Buffered |
Super PI 2M places (time in sec) |
| 2 | 386.30 | INT 2821 FLT 2786 |
INT 5830 FLT 5748 |
109 |
| 4 | 394.57 | INT 3218 FLT 3195 |
INT 5841 FLT 5818 |
107 |
While the differences in Quake3 frame rate and Super PI times are small, keep in mind that the only change here is using four SS DIMMs instead of two SS DIMMs. As predicted by Sandra UNBuffered Memory Test, the four SS DIMMs perform better than two SS DIMMs.
Comparing two SS DIMMs to two DS DIMMs was done using 2 x 256 MB SS OCZ PC4000 and 2 x 512 MB DS PC4000 at timings of 2.5-3-4-6 at 2.65V. It is almost impossible to keep DIMM capacity the same, which would be the most accurate test, as none of the samples using the same memory chips would have the same exact capacity in SS and DS configurations.
| 1000FSB (3.0GHz)/DDR500 Performance — OCZ PC4000 2 x 256 MB SS DIMMs vs. 2 x 512 MB DS DIMMs |
||||
| Number of DIMMs & Configuration | Quake3 fps |
Sandra UNBuffered | Sandra Standard Buffered |
Super PI 2M places (time in sec) |
| 2 SS | 392.30 | INT 2918 FLT 2926 |
INT 5761 FLT 5868 |
109 |
| 2 DS | 400.10 | INT 3282 FLT 3324 |
INT 5965 FLT 5934 |
106 |
Again, the differences are small but real in Quake3 and Super PI, but with 2 DS DIMMs performing better as we had demonstrated in Part 1 with the Sandra UNBuffered Memory Test.
The fastest configuration should be 4 Double-Bank DIMMs on the Intel 875 chipset motherboard. Our first efforts to test this configuration, with 4 x 256 DS OCZ 3700 GOLD modules did not show 4 DS DIMMs any faster than 2 DS DIMMs on the ASUS P4C800-E. This was a real puzzle considering that other predicted configurations were easily verified with Quake3, Super PI and other benchmarks. When we looked deeper, the problem became clear. In every configuration that we had tested with the ASUS P4C800-E, the Performance Mode showed “enabled” but with 4 DS DIMMs at any FSB speed faster than 800, CPU-Z 1.18C shows Performance Mode “disabled”. Our trial was failing here because we were comparing 2 DS DIMMs with PAT on to 4 DS DIMMs with PAT off. We have asked ASUS for the reason behind why PAT appears to be disabled at 4 DS DIMMs above 800FSB.
Since we were mainly concerned with comparing 2 DS with 4 DS DIMMs under the same conditions, we ran 2 DS vs. 4 DS tests at 800FSB/DDR400, so that PAT was enabled in both two and four DIMM setups. We compared prototypes of high-speed PC3700 memory that we tested, looking specifically at the performance of 2 x 512 MB DS to 4 x 512 MB DS at DDR400. Timings were 2-2-4-8 at 2.75V.
| 800FSB (2.4GHz)/DDR400 Performance 2 x 512 DS vs. 4 x 512 DS |
||||||
| Number of DS DIMMs | Quake3 fps |
UT2003 Flyby fps |
UT2003 Botmatch fps |
Sandra UNBuffered | Sandra Standard Buffered |
Super PI 2M places (time in sec) |
| 2 | 321.4 | 196.30 | 68.31 | INT 2683 FLT 2722 |
INT 4704 FLT 4691 |
133 |
| 4 | 324.5 | 197.60 | 69.38 | INT 2830 FLT 2923 |
INT 4678 FLT 4717 |
132 |
While the differences here are quite small, they still show 4 DS modules performing better than 2 DS modules. We suspect that we would see larger differences at higher speed, as we have in our other comparisons.
We have confirmed with game benchmarks and a number-crunching benchmark that the best 875/865 memory configurations can also be seen in real-world benchmarks. Because memory performance is only one component of game performance and overall system bandwidth, the effect on these benchmarks is, as expected, smaller than the variation seen in benchmarks that measure only memory performance, like Sandra UNBuffered Memory Test.
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Anonymous User - Friday, August 29, 2003 - link
This is quite confusing for a noob like myself, but I want to make the right purchasing decision, as I've never dabbled in overclocking, but hope to begin with this new setup.I'm waiting for the new Abit IC7-G Max III mobo to be released shortly. I'm targeting a P4 3.0C processor, and had been looking at Geil PC4000 platinum, though I suppose I should also now consider OCZ.
What processor and RAM combination on that motherboard will provide the best total results after overclocking? What part does the timing play in it? Will a 3.0C P4 not achieve as fast a bus speed as say, a 2.8C, meaning that a 2.8 would render ultimately the highest performance?
Any help is appreciated.
Anonymous User - Friday, August 29, 2003 - link
One thing I found odd was that there was no mention of cost. I picked up 1GB of Geil PC4000 Plat for $305 shipped which is considerably less than the RAM from all the other manufacturers. Given the results, that's a pretty sweet deal.Wesley Fink - Friday, August 29, 2003 - link
#63 -Please read the review. Not everyone had DS modules available at the time. We asked manufacturers for, at the minimum, 2 double-sided modules or 4 single-sided modules. This is because it would be unfair to compare performance of 2 SS modules to 2 DS modules.
Kingston was the only manufacturer who chose to supply 4 SS modules. We compare 4SS modules to 2DS in our review which IS fair. Results with 2SS modules were used to illustrate why you should use FOUR modules for best performance if they are SS.
oldfart - Thursday, August 28, 2003 - link
Wesley, don't get me wrong. I'm not trying to say 5:4 is "better" than 1:1. Why would it be?Not too long ago there were people who were adamant that unless you ran 1:1 ratio, you had a "crippled system". Another myth that was spread around was memory timings didn't matter on a DC DDR system (where the heck did that come from?).
People sold their PC3200 and got PC3700, ran 1:1 and got no performance increase or even a performance decrease and wondered why.
Websites were doing reviews that consisted of nothing but synthetic mem benches that showed 10x - 30x the performance gain that real world benches showed. These same sites are sponsored by memory manufactures selling that ram.
I guess I just got tired of all the misinformation being put out on the net.
Truth is right now, 5:4 low latency vs. 1:1 high latency produces ~ the same results. The actual difference is nothing you would ever notice in real usage. 1% one way or the other means nothing.
Once you can have high speed and low latency, things will change.
Anonymous User - Thursday, August 28, 2003 - link
Why are they benching 256MB Kingston modules against 512MB double-sided modules from all the other vendors? The tests clearly show 4 DS configuration is fastest. Why didn't they test 512MB Kingston DS modules? They are comparing apples to oranges at Kingston's expense.Wesley Fink - Thursday, August 28, 2003 - link
It seems that those proposing 5:4 is just as good or better always want to compare the WORST DDR500 timings to the BEST DDR400 timings. 2-2-2-5 is no more a typical DDR400 timing setup than 3-4-4-8 is at DDR500. Look at the timings that actually WORKED with DDR500. In fact, IF you can find DDR400 that can do 2-2-2-5 you will pay quite a premium for it - just like you do for DDR500.Also the DDR550 we achieved with the best DDR500 would need to be compared to 5:4 at DDR440 running at 2-2-2-6 or so, and the 300FSB some achieve with the 2.4C would need DDR480 - just to run 5:4. With a CPU that achieves high FSB, the DDR500 may be the best choice EVEN at 5:4.
I do think it is a mistake to overlook how very good 5:4 can perform with FAST timings memory, but I also think it is a mistake to pretend 1:1 doesn't matter in performance - because it does. It is ONE of the things that matters, but by no means the only thing.
I am looking right now at some DDR533 Engineering Samples that run 2.5-2-3-6 at DDR533. When these and other faster timing DDR500+ are released, this argument will disappear. BOTH speed and timings matter - and neither is the complete picture.
This review goes into great detail to point out that DDR500 is NOT needed by everyone, and in fact requires a setup that can actually RUN at 250 (1000 FSB) to get ANY benefit. We also pointed out that for most with a 2.8 to 3.2 CPU that a slower memory with faster timings would be a much better choice for performance.
oldfart - Thursday, August 28, 2003 - link
I didn't compare all the results, but looked at the Q3 numbers compared to other reviews that have done the same testing. I'll use the Corsair 4000 numbers:Your review
XMS4000 DDR500 1:1 400.2 FPS
PC 3500 DDR400 5:4 393.7 FPS
This test:
http://www.hardtecs4u.com/reviews/2003/ddr400_roun...
XMS4000 DDR500 1:1 3-4-4-8 340.8 FPS
XMS3200 DDR400 5:4 2-3-2-6 338.9 FPS
Numbers are very close. 2-2-2-5 would have been faster if run that way.
***********************
This test:
http://www.ocprices.com/index.php?action=reviews&a...
XMS4000 DDR500 1:1 3-8-4-4 320 FPS
XMS4000 DDR500 1:1 2.5-7-4-4 338 FPS
XMS3200 DDR400 5:4 2-5-2-2 340.5 FPS
In this test, the PC3200 low latency is a bit faster than the PC4000 with medium timings, quite a bit faster than the slowest timings.
In all of these tests, the difference is very small when it comes down to it. A tie is more accurate.
My points:
1)the people who think they are "crippling" their P4 rig by running a mem ratio are mistaken. You can get the same performance if you set it up right
2) SiSoft mem benches do not represent real world performance. They show an inaccurate view of system performance gains.
3) Certain site push PC3700/4000 too hard and neglect to show that equal performance can be had with less expensive ram.
4) I hate posting this here!! Bring back the AT articles forum!
Wesley Fink - Thursday, August 28, 2003 - link
#35, #38, #44, #49, #50, #52, #55, #57 -To answer your question, we ran 1000FSB (500) at 5:4 with Mushkin PC3500 Level II at CAS 2-2-2-5. This Mushkin is about the only memory left that can REALLY do 2-2-2-5 at DDR400, and a review will be up soon. The testbed and ALL hardware and settings were the same as this review. Results are:
Sandra UNBuffered - 2964/2959 or avg. 2962
Sandra Buffered (Standard) – 5470/5468 or avg. 5469
Quake 3 – 393.7fps
UT2003 – Flyby: 241.84
Botmatch: 87.66
SuperPI (2M places) – 105s
Write these numbers down and compare them to Page 14 (500FSB/DDR500) charts. You will see that 5:4 2-2-2-5 is very close to the performance of the poorer DDR500 in our tests, but it does NOT beat the DDR500.
We are comparing the fastest memory I have tested at DDR400, at it’s fastest 5:4 timings, to DDR500 at much poorer timings. Of course the DDR400 goes even higher than DDR500 and performs even better.
BOTH timings and FSB speed matter, and the answers are not as simple as some have stated.
vailr - Thursday, August 28, 2003 - link
Please consider adding TwinMos 3700 to your updated review.http://www.showtimecomputer.com/cpumem/ddr.asp
quote: "
512 MB PC3700 400 (DDR/CL2.5 Twinmos Chip $119.00
512 MB PC3700 400 (DDR/CL2.5 Winbond Chip $125.00
TwinMOS stays one step ahead of the technology curve by launching one of the first PC3700 Unbuffered DIMM Modules. Featuring speeds up to 466Mhz, PC3700 DDR 466 delivers enhanced bandwidth up to 3728MB per second.
Check it Out: WWW.TwinMOS .COM "
Slappy00 - Thursday, August 28, 2003 - link
Ill say one thing about OCZ, wheather or not the review is bias in any way, ocz has come a long way to prove that they have a good product and stand by it. I have read countless posts where OCZ would gladly RMA some user's memory and give them pretested memory as a replacement. I for one bought GEiL pc4200 (really pc4000 with looser timings) and wish I had the kind of support offered by OCZ.In the end I would only use results based on reviews as a guide not a reference.
For example:
I have an Abit IS7 (BIOS 16) and my board will not do anything faster than 260 1:1 (520DDR) without memory errors (via memtest86), but I can run the timings more aggreesively (2.5-8-4-4) at 260 for some reason. I cant use any dividers (5:4 3:2) and I cant use GAT or I get the dreaded long beep at boot-up.
just goes to show you that just because its printed doesn't mean it's right for you.