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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Anonymous User - Monday, July 28, 2003 - link
Great article. Pity Im too late. Is single sided RAM the same as single bank (electronic) or physically the ram chips are on a single side of the stick. Mushkin in particular are wary of using the single side term. Also What about PAT acceleration in conjunction with lower latency RAM and DIMM number? Some reviews have shown lower FSB with tight timings RAM and PAT acceleration beating looser timings 1:1 higher FSB RAM systems. Ah questions questions?pakuens - Monday, July 28, 2003 - link
Good article. I'm right in the middle of buying memory and it answered several questions. It saved me from an expensive mistake, as I was considering using two matched pairs, but of differing size.I like the unbuffered benchmark method.