I have been trying various overclock tests and quite often I get a lock-up wilst running Prime95 on 'lots of everything' test after about 10 minutes with the CPU clock >375. If I run the 'lots of cpu a little ram' test then the machine is stable. If I run with a CPU clock <375 I can do the 'lots of everything' test indefinitely.
Using Speed Fan I can see the CPU temp at 50-60 and core0 at about 68 in the worst cases. Is this too high?
Do you think the lock-up is due to the NorthBridge overheating because lot's of ram is being tested which puts the NB through it's paces and it can't take it? I'm thinking the problem is heat as it takes about 10 minutes on full load to expose the problem.
It looks quite difficult to cool the NB as it is half under the first HD4870 graphics card and the next HD4870 is not far away! I'm thinking of trying to squeeze a small fan on top of it and see if that helps.
I can go through this more methodically if someone from gigabyte is listening.
On another note, is it worth me installing the beta bios? I used to be running it for ages but I had a checksum error on the bios yesterday and it reverted back to F5.
Any help is greatly appreciated. I'm sure it's possible to get this system to run with an FSB of 1600Mhz / 1700Mhz stable.
ARTIC COOLING FREEZER 7 CPU Cooler
Corsair HX1000W PSU
Crucial Ballistix 4x1Gb DD2 1066Mhz PC28500
HD4870 512Mb x 2 Crossfire