Searching for the Memory Holy Grail: Part 1
by Wesley Fink on July 27, 2003 11:13 PM EST- Posted in
- Memory
Performance Tests
Double-Sided Memory
| DDR400, 800FSB (200x4) Intel 875 Chipset, 2-7-3-3 Memory Timings OCZ3700 GOLD 256MB DS |
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| Number of DOUBLE-Sided DIMMS | MemTest86 MB/Second |
UNBuffered Sandra 2003 Memory Test (MB/Second) |
Buffered (Standard) Sandra 2003 Memory Test |
| 1 | 1671 | 1790 INT 1837 FLT |
2974 INT 2972 FLT |
| 2 | 2544 | 2600 INT 2660 FLT |
4769 INT 4710 FLT |
| 4 | 2489 | 2861 INT 2848 FLT |
4714 INT 4693 FLT |
| DDR466, 932FSB (233x4) Intel 875 Chipset, 2-7-3-3 Memory Timings OCZ3700 GOLD 256MB DS |
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| Number of DOUBLE-Sided DIMMS | MemTest86 MB/Second |
UNBuffered Sandra 2003 Memory Test (MB/Second) |
Buffered (Standard) Sandra 2003 Memory Test |
| 1 | 1947 | 2046 INT 2145 FLT |
3447 INT 3456 FLT |
| 2 | 2964 | 3192 INT 3247 FLT |
5614 INT 5584 FLT |
| 4 | 2900 | 3421 INT 3455 FLT |
5604 INT 5609 FLT |
As you can see from the benchmarks above, SiSoft Sandra UNBuffered is a more sensitive benchmark for determining differences in memory performance than the Standard Buffered test – which can sometimes conceal differences in memory performance with buffering techniques. It also appears to be more sensitive than MemTest86 in determining memory bandwidth. This is particularly clear in the benchmarks for two and four double-sided DIMMs in Dual-Channel mode. Standard buffered benchmarks and MemTest86 show the performances of two and four double-sided Dimms as fairly equal, while UNBuffered benchmarks show that four double-sided DIMMs are about 7 to 10% higher in performance – a significant increase.
Later in the review, you will read confirmation from a respected source that the UNBuffered Memory Test results are a better reflection of what is really happening in memory performance on the 875/865 chipsets when comparing two versus four DIMMs. Therefore, for the remainder of tests, we will only use Sandra UNBuffered Memory Test and MemTest86 for benchmarking.
| DDR500, 1000FSB (250x4) Intel 875 Chipset, 2.5-7-4-4 Memory Timings OCZ3700 GOLD 256MB DS |
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| Number of DOUBLE-Sided DIMMS | MemTest86 MB/Second |
UNBuffered Sandra 2003 Memory Test |
| 1 | 1953 | 2193 INT 2203 FLT |
| 2 | 2821 | 3051 INT 3129 FLT |
| 4 | 2821 | 3318 INT 3467FLT |
Single-Sided Memory
| DDR500, 1000FSB (250x4) Intel 875 Chipset, 2.5-7-4-4 Memory Timings OCZ4000 GOLD 256MB SS |
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| Number of SINGLE-Sided DIMMS | MemTest86 MB/Second |
UNBuffered Sandra 2003 Memory Test |
| 1 | 1924 | 2076 INT 2090 FLT |
| 2 | 2551 | 2725 INT 2762 FLT |
| 4 | 2821 | 3254 INT 3194FLT |
Single-sided modules appear to perform very differently on the Intel 875/865 chipsets than double-sided modules. Both MemTest86 and Sandra UNBuffered Memory Test show that four single-sided DIMMs perform much better than two. The UNBuffered Sandra benchmark shows an improvement of almost 20% in performance when using four Dimms instead of two. This is more than double the UNBuffered Performance improvement in going from two DS DIMMs to four DS DIMMs on the 875/865 chipsets
UNBuffered Memory Performance Summary
Having established that the SiSoft Sandra UNBuffered Memory Test is a sensitive benchmark for measuring performance differences in memory configuration, it is now useful to compare UNBuffered Memory Benchmarks for one, two, and four double-sided and single-sided DIMM modules.
| UNBuffered Memory Benchmark 875/865 | ||||
| Number of DIMMS | DDR400/800FSB DOUBLE-SIDED |
DDR466/932FSB DOUBLE-SIDED |
DDR500/1000FSB DOUBLE-SIDED |
DDR500/1000FSB SINGLE-SIDED |
| 1 | 1790 INT 1837 FLT |
2046 INT 2145 FLT |
2193 INT 2203 FLT |
2076 INT 2090 FLT |
| 2 | 2600 INT 2660 FLT |
3192 INT 3247 FLT |
3051 INT 3129 FLT |
2725 INT 2762 FLT |
| 4 | 2861 INT 2848 FLT |
3421 INT 3455 FLT |
3318 INT 3467FLT |
3254 INT 3194FLT |
In all cases, on both 865 and 875 chipsets, with both single-sided and double-sided DIMMs, four DIMMs is the best performing memory configuration at DDR400(1:1) or higher speed. This may come as a surprise to many of you looking for memory for your 865/875 motherboard. As expected, two DIMMs in dual-channel memory configuration performed better than a single DIMM in all cases. Beyond this, we see that two double-sided DIMMs perform much better than two single-sided DIMMs, but that four single-sided DIMMs perform almost as well as four double-sided DIMMs.
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42 Comments
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Anonymous User - Sunday, August 31, 2003 - link
This single/double side/bank issue is very misunderstood. To further confuse things the memory manufacturers, who finally getting better about reporting full timing numbers, generally don't publish the side/bank count. I'd like to see an article that helps identify whose memory is really double banked, especially at the 256MB level, since its going to take 4 modules for best performance in an 875 system. Since many of these products are best available thru the internet, I don't have the luxury of looking at the modules before I buy.FYI, I'm also more interested in using well matched double banked components with low timings than in overclocking to the max.
Mushkin has very low timing memory in a 512MB configuration that is double-banked, but it seems like overkill to put 2GB of memory for $800+ into the system at this point. (I also don't know how well the system would perform with this quantity of memory as I hear that more memory can slow timings down.) Their 256MB modules are single-banked unfortunately.
Anonymous User - Monday, August 18, 2003 - link
I would personally buy the Mushkin PC3200 Level II Dual Pack located at this URL: http://www.mushkin.com/epages/Mushkin.storefront/3...It says that is is CAS 2-2-2 at 400MHz
Unfortunately, Anandtech has not added Mushkin to their test products for any of these articles (not that I have seen at least) so I cannot verify the performance. I hope this due to Mushkin not supplying them samples before they complete testing and go to press. Otherwise, it is just a gross oversite by Anandtech not to include Mushkin. Whatever the case, Mushkin is a big name company with many supporters who will vouch for their quality. I am going to upgrade my memory shortly to these exact DIMMs so I feel comfortable suggesting them. 2-2-2 latency just sounds too good to pass up.
Cheers,
Wiley
DaveH - Tuesday, August 12, 2003 - link
What about running slower RAM in the newer chipsets? Like PC2100 in 800 FSB?Anonymous User - Monday, August 11, 2003 - link
My personal SiSoft Sandra Memory Bandwidth UNBuffered test results on a Gigabyte 8KNXP (F5 BIOS) with a P4 3Ghz/800Mhz, ATI9800 Pro 256mb, SB Audigy:Mushkin PC3500 Level II Black
4x512mb, 200mhz, 2-2-2-6, 2955/3017
4x512mb, 217mhz, 2-2-2-6, 2850/2916
2x512mb, 200mhz, 2-2-2-6, 2844/2862
2x512mb, 217mhz, 2-3-2-6, 2423/2493
Corsair TWINX1024-3700
4x512mb, 200mhz, 3-4-4-8, 2724/2782
4x512mb, 217mhz, 3-4-4-8, 2614/2723
2x512mb, 200mhz, 3-4-3-8, 2610/2626
2x512mb, 217mhz, 3-4-3-8, 2491/2542
Anonymous User - Thursday, August 7, 2003 - link
Need help determining SS vs DS (Single side/bank vs. Double Side/Bank) - how can you tell, as the memory mfgrs don't usually say?Rayalkj - Thursday, August 7, 2003 - link
How similiar does the RAM have to be? I bought a Dell with 2x128 meg ram and want to up it to 512 megs. Do I need the exact same Brand? Just the same sizes? (ie. 2 more 128 meg sticks) Is there something I should look for especially?... Yes, I am a bit of a noob at this stuff
Anonymous User - Wednesday, August 6, 2003 - link
Would this apply to nForce2 Ultra chipsets?Wesley Fink - Sunday, August 3, 2003 - link
Regarding "Mixed Memory" configurations, the Best Memory Timings are the fastest timings THAT PARTICULAR COMBINATION WOULD RUN. So they are the best timings for that mix of Dimms. Mixed pairs - particularly widely different memory pairs - can take a very large performance hit in 865/875 boards. The reduction in performance is MUCH greater than we would expect.As was also stated, we have seen cases of 2 pairs of dimms from different manufacturers that match closely on capacity and timings that perform just as well as 2 matched pairs.
Anonymous User - Sunday, August 3, 2003 - link
Re: "Intel’s White Papers address mixed memoryconfigurations only to say that they will work,
but they will default to the slowest speed and
SPD timings of the mixed DIMMs."
I wish I understood this. I am pretty sure that
I don't. For example, in the first row of the
mixed memory benchmark table the "best memory
timing" is given as 2-7-3-3 but the 512 MB DIMMs
are said to run at 2-5-2-2. Could it be that this
column should be labelled "worst memory timing"?
And suppose that the 512 MB memory was run at the
slower timing, 2-7-3-3, instead of 2-5-2-2.
How does that result in a 25% performance loss?
I would really like to understand this so that
I could predict what will happen when I mix
memory timings, avoid really bad DIMM
combinations and be able to use the not so bad
combinations. So, can someone explain what it
really going on here?
MS - Friday, August 1, 2003 - link
I'll certainly run a few benches myself. It is really interesting that those guys who should know, that is memory and chipset manufacturers are lagging so far behind the "fanboy" community in terms of understanding how things actually work and what factors are really important.As far as your review goes, I am eager to see it, especially the acknowledgement (LOL)
Michael