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Memory latency


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My new Corsair TWIN2X1024-5400C4PRO is SPD programmed at 4-4-4-12. Sanda reports it is running 4-5-5-15, slower than the stock Samsung DDR-2 PC4300 reported as running at 4-4-4-11. The Gateway BIOS for the Intel D945GBI board does not report or allow adjustment of memory parameters. It appears that the 200FSBx4=800 is running at 4:3 or 533. Intel says the board is capable of 667 (5400), but without BOIS adjustment, it appears fixed at 533 (4300). Am I getting 533 with 4-5-5-15 latencies? If I returned the 5400C4PRO (15% restocking fee) for say Corsair TWIN2X1024-4300C3 would I get 533 with 3-3-3-8 latencies? Voltage appears fixed at 1.8V. Would the Corsair 4300C3 tested at 1.8V or the GeIL DDR2 533's rated at 1.8 to 2.4V be stable at their stated 3-3-3-8 latencies if fixed at:o: 1.8V? Any test program that reports acutal memory parameters when BIOS won't tell you?

Thank you.

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There's no way to override the auto BIOS settings. CPU-Z will tell you the actual memory timings under the MEMORY tab.


Actually, most OEM motherboards (which are, motherboards that are specific to big-name OEM systems) run on fixed, JEDEC-approved (or JEDEC-standard) CAS and RAS timings for any given memory clockspeed. What that means is that DDR2-533 memory will always run at CAS 4-4-4-11 timings on that Gateway system no matter which DDR2-533 memory modules that you use. And DDR2-667 modules will always run at CAS 4-5-5-15 timings.


Same thing with my brother's Dell Dimension 8300 system: Though it uses the i875P chipset, PAT cannot be enabled at all whatsoever with that motherboard, and all memory will run at a fixed set of CAS 3-3-3-8 timings @ DDR400 regardless of which memory modules he used. What's more, if anything, the i875P-based systems with PAT disabled will actually have a lower memory bandwidth, and therefore slower performance, than any i865PE-based system.


In all of the above instances, the SPD is used only to set the memory clockspeed.


Those factors, combined with the relatively low, JEDEC-standard voltage output of the memory slots, leave the OEM system owner with the System Select modules as the best choice for OEM systems (and BYOPC systems which lack user-adjustable DDR voltage), since most widely available, store-bought DDR and DDR2 memory requires a higher voltage than the JEDEC standard for optimal stability.

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