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Thread: tRC = tRAS + tRP
07-04-08, 06:29 PM #1
tRC = tRAS + tRP
I have 2x1gb of Crucial Ballistix DDR2-800 4-4-4-12
I am getting some instability at DDR2-960 5-5-5-15
In SPD (EPP #2) it's rated at 500mhz, 5 (CAS)-5 (RAS to CAS)-5 (tRP)-15 (tRAS)-30 (tRP)-2T
Since my motherboard is not a nvidia board, I have to set the EPP settings manually.
My motherboard (GA-EP35-DS3L) would not let me set tRC manually, so I looked it up on Google.
Apparently tRC = tRAS + tRP, but that is very strange, because the EPP first says tRAS = 15, tRP = 5, giving a tRC = 20, and then says tRC should be 30. How should I set it?
07-04-08, 07:02 PM #2
It seems like the formula is actually tRC >= tRAS + tRP as opposed to tRC = tRAS + tRP.
Can someone please confirm/correct it?
That makes sense, then.
Since tRC cannot be set on P35 boards (BIOS sets it automatically), to guarantee a minimal tRC of 30, I am running it at tRP = 8, tRAS = 22. Seems to be stable so far. Is it a good idea? (I increased those values by those amounts randomly)
btw, are memory modules guranteed to run at EPP settings? (can I RMA them if they don't?) Or are they just suggested OC settings that may not work?
07-04-08, 07:02 PM #3
I set, cl, trcd, trp, tras, and leave everything else on auto. Also don't forget about setting voltage
07-04-08, 07:22 PM #4
That's what I did, and it's unstable (at 2.2V, the maximum rated voltage).
I have to set the tRC (by setting tRP and tRAS) to get it stable.