so I've had a lot of time to fiddle with this new shinny sandy bridge memory. setup is as follows:
i5 2500k
Gigabyte P67A-UD4
G.Skill F3-17000CL9D-8GBXLD @ 2133MHz 1.66v set in bios, 1.68v detected (one kit, two sticks)
GeForce GTX580
the XMP profile works fine, and according to the MIT status screen it sets the ram at:
tCL 9
tRC 11
tRP 9
tRAS 28
tRRD 7
tWP 28
tRFC 200
tCMD 2
with Manual/Auto instead of using the XMP profile, my board sets the same timings except it seems tRFC goes from 200 to 170. both 200 and 170 are stable but 170 benches slightly better. but which one is right?
and what are the optimal subtimings for the F3-17000CL9D-8GBXLD kit? is there anything I can lower here? this is the full subtimings with my board on manual/auto, I can't tell what the XMP profile sets some of these to though.
tCL 9
tRC 11
tRP 9
tRAS 28
tRC 46
tRRD 7
tWTR 8
tWR 16
tWTP 28
tWL 8
tRFC 170
tRTP 8
tFAW 32
tCMD 2
and I know I'm asking for a lot from these sticks, but I've had a really tough time getting tCMD (command rate) down to 1T. I know it makes a small difference but I've always been really **** about command rate, even since the Athlon64 days. and I've wondered why so many g.skill are rated for 2T, my old 2000MHz mushkin stuff was 1T even. (although not sandy bridge compatible)
It passes memtest fine with 1T, so I think the RAM will run 1T right? but I'm guessing the CPU doesn't like it? I get memory related BSOD's (0x109, 0x0A, 0x50) only after hours of stress testing with prime95 using 5-6 GB of memory.
What voltages would help me run 1T? I've been at my wits end fiddling with QPI/VTT and such but to no avail. What is limiting me? Is it that the RAM? or the CPU/motherboard? I need to find the weak link so I know what voltage to play with!
TLDR version
i5 2500k
Gigabyte P67A-UD4
G.Skill F3-17000CL9D-8GBXLD @ 2133MHz 1.66v set in bios, 1.68v detected (one kit, two sticks)
GeForce GTX580
the XMP profile works fine, and according to the MIT status screen it sets the ram at:
tCL 9
tRC 11
tRP 9
tRAS 28
tRRD 7
tWP 28
tRFC 200
tCMD 2
with Manual/Auto instead of using the XMP profile, my board sets the same timings except it seems tRFC goes from 200 to 170. both 200 and 170 are stable but 170 benches slightly better. but which one is right?
and what are the optimal subtimings for the F3-17000CL9D-8GBXLD kit? is there anything I can lower here? this is the full subtimings with my board on manual/auto, I can't tell what the XMP profile sets some of these to though.
tCL 9
tRC 11
tRP 9
tRAS 28
tRC 46
tRRD 7
tWTR 8
tWR 16
tWTP 28
tWL 8
tRFC 170
tRTP 8
tFAW 32
tCMD 2
and I know I'm asking for a lot from these sticks, but I've had a really tough time getting tCMD (command rate) down to 1T. I know it makes a small difference but I've always been really **** about command rate, even since the Athlon64 days. and I've wondered why so many g.skill are rated for 2T, my old 2000MHz mushkin stuff was 1T even. (although not sandy bridge compatible)
It passes memtest fine with 1T, so I think the RAM will run 1T right? but I'm guessing the CPU doesn't like it? I get memory related BSOD's (0x109, 0x0A, 0x50) only after hours of stress testing with prime95 using 5-6 GB of memory.
What voltages would help me run 1T? I've been at my wits end fiddling with QPI/VTT and such but to no avail. What is limiting me? Is it that the RAM? or the CPU/motherboard? I need to find the weak link so I know what voltage to play with!
TLDR version
- Is 170 or 200 tRFC the proper subtiming?
- What are the full optimal subtimings?
- Can the RAM handle 1T CR?
- What is holding me back from lowering command rate to 1T? CPU? Memory controller?QPI? motherboard? I need to know the weak link!
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