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ROGBot
I just got a 64gb kit of Corsair Dominator Platinums (CMD64GX3M8A2400C11) and I've paired it with a 3960x at 4.8ghz. The system is confirmed 24 hours Prime95 stable. In the BIOS, CPU-Z, Speccy, AIDA64 it shows the memory running correctly at its XMP profile at 2400mhz @ 11-13-13-31-2T with all 64gb memory in quad channel.
When I run 3DMark however, the physics score is abysmal, similar to a stock 2500k. Looking into this problem, I looked at AIDA64 memory benchmark, with the following results:
When downclocking the memory to 2133mhz using the same 11-13-13-31-2T timings, the read/write/copy speed appears to be normal, albeit on the low side at ~57000 / 59000 / 56000.
Can anyone help?
When I run 3DMark however, the physics score is abysmal, similar to a stock 2500k. Looking into this problem, I looked at AIDA64 memory benchmark, with the following results:
When downclocking the memory to 2133mhz using the same 11-13-13-31-2T timings, the read/write/copy speed appears to be normal, albeit on the low side at ~57000 / 59000 / 56000.
Can anyone help?
Memory bandwidth will drop dramatically like that when
1. The CPU is using less than all cores/threads - check in Aida64 that all 6 cores are in use
2. The number of DIMMs is reduced. - check in Aida 64 that all 8 sticks are listed. Further, check in BIOS GPU/DIMM Post to see that all the sticks are recognized by BIOS when set to 2400.
The most likely case is that the 3960X IMC cannot do 2400MHz. Mine couldn't and I had to back off to 2133. Perhaps one of the IMC channels can do 2400, but the others can only do 2133. Possible solutions are:
1. run at 2133 and take the lower bandwidth
2. switch to a 3970X or one of the IvyBridge CPUs that regularly do 2400 RAM - 3970X, 4930K and 4960X have worked at 2400 for me. Even with RAM easily capable of 2666, I have to run at 2400 with those CPUs and 2133 with a 3960X.
Jeff
1. The CPU is using less than all cores/threads - check in Aida64 that all 6 cores are in use
2. The number of DIMMs is reduced. - check in Aida 64 that all 8 sticks are listed. Further, check in BIOS GPU/DIMM Post to see that all the sticks are recognized by BIOS when set to 2400.
The most likely case is that the 3960X IMC cannot do 2400MHz. Mine couldn't and I had to back off to 2133. Perhaps one of the IMC channels can do 2400, but the others can only do 2133. Possible solutions are:
1. run at 2133 and take the lower bandwidth
2. switch to a 3970X or one of the IvyBridge CPUs that regularly do 2400 RAM - 3970X, 4930K and 4960X have worked at 2400 for me. Even with RAM easily capable of 2666, I have to run at 2400 with those CPUs and 2133 with a 3960X.
Jeff
