Did you read this item about Abit GAT settings on the Mushkin support page?
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USER TIPS: enabling any of the different performance options will override the manual latency and frequency ratio settings and force a 1:1 CPU
RAM ratio at 2:x:x:x latency settings, with the "Ultra" (now "F1") setting forcing a 2:2:2:5 latency configuration at DDR400 frequency.
We also found that using the "Turbo" (or "Street Racer") setting at 2:2:2:7 yields overall better performance since a longer tRAS prevents the controller from inadvertently terminating an ongoing data burst. Enabling the CPC (Command Per Clock) adds another small notch to the overall performance but can cause stability problems as well. The Read Delay timer should be set to 5-6 cycles for best stability and performance or else left on Auto.
We found that DIMMs that require CAS latencies of 2.5 or higher at DDR400 will not function in any of the available performance modes. The workaround is to set the performance tab to "Disabled". Even though this appears counterintuitive at first, it makes sense in that there is no point in reducing chipset latencies when the memory itself would add those latencies again at the back-end of the "food chain". The HW monitor shows voltage values that are below the real voltages, so better not crank them up too much.
Keep in mind that these recommendations are based on "snapshots" of a few of the current BIOS revisions and may change with future BIOS versions.
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With Buffalo Tech PC3700 on an Abut IC7, I've got my ram set to the best timings I can manage, 2.3.2.6 @ 220mhz running 5:4. That gives me a 275 fsb and takes my P4C 2.4 to 3.3g. All benches, including memory, are right where they ought to be.
With the GAT settings at anything but auto, the system becomes unstable. On auto, it will loop MemTest and Prime95 without a hiccup at the above settings.
I've pretty much come to the conclusion that GAT is for those running 1:1 who don't know how to tweak their own memory settings. If you're overclocking at 5:4 or using higher latencies for a higher fsb, GAT will do more harm than good.
In any case, it seems to be a real crap shoot, working for some and causing serious problems for others.
The biggest frustration is that Abit has yet to reply, so far as I know, to any of the many requests from reviewers and customers wanting to know what those settings actually DO.
"Rieper" wrote:
I'm running my Mushkin Black Level II PC3500 (rated 2-2-2-5) at normal
stock
FSB 200MHz. I'm using SPD timings (2-2-2-5) and when changing the performance to anything but auto (ie. Turbo, Street Racer, F1) I get a
FATAL
ERROR in prime95.
MemTest checks out okay after hours of testing, but not so with Prime95. After the third line of prime95 I get a FATAL ERROR message.
So I'm thinking of upping the DDR voltage instead of sending the memory right back to Newegg. Any ideas how high I can safely up the voltage to acheive stability? Thanks in advance.
S.Anderson
