Performance Tests

Double-Sided Memory

DDR400, 800FSB (200x4)
Intel 875 Chipset, 2-7-3-3 Memory Timings
OCZ3700 GOLD 256MB DS
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
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
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
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.

Performance Test Configuration Intel White Papers Confirm Results
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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.

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