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How to get quicker latency, timings?

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ehume

Member
Joined
Oct 30, 2009
I have DDR3 memory. I have learned that pushing clock speed beyond 1066MHz makes little difference, but reducing latency and timings speeds performance. I would like to bring down my 9-9-9-24 timings to something less.

I have G.SKILL Ripjaws DDR3 2000 (PC3 16000) F3-16000CL9D-4GBRH, which is 2000MHz at 1.65V, 1333MHz at 1.5V (default for my MB).

Do I raise the voltage to support lower timings? Stay at 1.5V?

The CPU is i7 860. The MB is Gigabyte GA-P55M-UD2.

Thanks
 

Rich'[ard]

Member
Joined
Apr 28, 2008
Location
Melb, AUS
ddr3 memory's purpose is for higher bandwidth over ddr2 memory. this is because of the new design of the i7 CPUs, compared to ddr2 and LGA 775 CPUs.

what you're saying about pushing ram over 1066mhz only applies to older Intel Core 2 cpus becuase not many people need such a high FSB, (unless they need ram at 1066mhz+ for benchmarking).

i'm not sure how RAM is linked to the CPU for i7 cpus...but you certainly shoudln't be runing them as low as 1066mhz when you have 2000mhz kits. G-skill made them for a purpose...not just for the $$.

to lower timings, you may not have to increase the voltage. you only change the voltage when your PC is unstable with whatever timings/speed you select.
 
OP
ehume

ehume

Member
Joined
Oct 30, 2009
You're right, of course.

Best settings with a BCLK of 133:

Multiplier of 12, for a nominal bandwidth of 1600MHz. Slower speeds do allow lower latencies, but there is no real improvement in latency and "speed factor" (a SiSoft measurement of cache speed to DRAM speed). And the bandwidth is signifcantly slower.

Lowest timings: 7-7-7-22. 7-7-7-21 is no better and often worse.

I have found the tRC set at AUTO (33 for this board) is optimal: Set at 29 (tRAS + tRP), there is no better result; I see no need to unduly tighten settings, as that might make memory less stable.

DRAM voltage is set to AUTO, so it is running at 1.616V right now, less than the 1.65V cap but more than the 1.5V in the profile.

My theory going into this experiment was that with a normal (1333) or lower speed, the lower latencies would produce better performance. That was wrong. The biggest boost comes from setting the multiplier to give a DDR speed of 1600MHz.

Now I know what you already knew.