ziddey
03-13-2007, 08:02 PM
I figured there should be a guide stickied for memory timings and how to tweak them. As it is right now, the general idea is that tighter is usually better, but not always, and that everyone should test out settings to find what works best.
It probably wouldn't be a bad idea to have a thread where we post what works and what makes things worse.
Here's what I've found:
My latest sticks of d9gmh have trouble running 400mhz cas3, even with 2.37v. So I tried tuning with cas4. I was able to get 4-3-3 stable. However, I found that overall latency was greatly reduced. Using mbench, I was seeing access latencies in the mid 60's with 4-3-3 and in the 200's for clocks.
Once I change to 4-4-3, latencies drop right into the higher 50's. Changing to 4-4-4 was the best, with slightly better latencies and clocks, which were in the 180's.
It looks like the rule of thumb is to not set ras-to-cas and ras precharge lower than cas.
As far as subtimings, I've found the differences to be more negligible. I haven't tested extensively yet though. It does seem like Trfc, lower is better.
SPD settings at lower speeds show subtimings at 3-9-4-11 (order asus shows. tRRD, tWTR, tRTP, write to precharge delay). I've found I've been able to lower the last one to 10, but the others don't seem to go lower. I haven't seen much difference in setting these compared to the asus default loose subtimings of 10-10-10-11.
It probably wouldn't be a bad idea to have a thread where we post what works and what makes things worse.
Here's what I've found:
My latest sticks of d9gmh have trouble running 400mhz cas3, even with 2.37v. So I tried tuning with cas4. I was able to get 4-3-3 stable. However, I found that overall latency was greatly reduced. Using mbench, I was seeing access latencies in the mid 60's with 4-3-3 and in the 200's for clocks.
Once I change to 4-4-3, latencies drop right into the higher 50's. Changing to 4-4-4 was the best, with slightly better latencies and clocks, which were in the 180's.
It looks like the rule of thumb is to not set ras-to-cas and ras precharge lower than cas.
As far as subtimings, I've found the differences to be more negligible. I haven't tested extensively yet though. It does seem like Trfc, lower is better.
SPD settings at lower speeds show subtimings at 3-9-4-11 (order asus shows. tRRD, tWTR, tRTP, write to precharge delay). I've found I've been able to lower the last one to 10, but the others don't seem to go lower. I haven't seen much difference in setting these compared to the asus default loose subtimings of 10-10-10-11.