We tested six different memory products : GeIL DDR2-667, Kingston DDR2-900, OCZ DDR2-800, Samsung DDR2-667 and the DDR2-1000 DIMMs from A-Data and Corsair. All review samples with the exception of the DDR2-1000 DIMMs were confronted with products that we bought in retail. Our intention was to compare whether the memory companies had submitted cherry-picked samples for our memory roundup.
In the beginning, one of test systems failed to meet our expectations. We had used a Pentium D processor that we believed was capable of working reliably at overclocked speeds after initial testing. This, however, was not the case in the stress test setup any more and the system crashed while the GeIL memory was tested. After exchanging the processor by a more powerful Pentium Extreme Edition 955, we repeated the test run. Here is a list of all results :
|Memory Live Stress Test - Results|
|Product||Review Sample||Retail Memory||Delta|
|GeIL DDR2-667||DDR2-942||DDR2-942||0% discrepancy41% overclocking|
|Kingston DDR2-900||DDR2-942||DDR2-952||+1% discrepancy5.7% overclocking|
|OCZ DDR2-800||DDR2-946||DDR2-910||-3.8% discrepancy,13.8% overclocking|
|Samsung DDR2-667||DDR2-722||DDR2-842||+16.6% discrepancy26.2% overclocking|
All memory modules were capable to run at clock speeds that were beyond the specifications. The Kingston DIMMs prodived the smallest overclocking margin (5.7%), but the DDR2-900 parts are very high-end anyway. GeIL’s and Samsung’s DDR2-667 products achieved excellent results by exceeding the DDR2-800 line. Samsung hit DDR2-842, which shows a 26% overclocking potential, while GeIL crashed at DDR2-942. This corresponds to a 41% overclocking margin. OCZ’s high-performance DIMMs also managed to hit DDR2-910.
Memory vendors are capable of assembling mass production DIMMs at a clock speed tolerance of approximately 2-3%. All stress test DIMMs were within these boundaries, which shows that retail memory products are as capable as the samples we received for review. Yet assume that many vendors would hand-pick their review samples.
The the outcome also shows that there is a sweet spot for current DDR2 memory. All products reached at least DDR2-800 speeds ; most of the DIMMs were capable of running at DDR2-900 level. While you should never hope for retail memory to reach the same clock speeds as review samples, you can certainly expect all available quality DDR2 memory to hit the 400 MHz mark (DDR2-800) at slightly increased voltages.