i have run 8gb of crucial ballistix tracer with a p2 940 and 955 and found no problem what so ever.. board was an m3a79t
here were my results from everest. (sorry i didnt record the cpu speed of the 940 i think they were at 3.8ghz)
x4 940
fsb 230 1:2 ddr2 460mhz 4-4-4-12-24 @ 2.1v (920mhz) ganged
read: 8908mb/s
write: 6957mb/s
copy: 10070mb/s
latency: 51.5ns
1080mhz 5-5-5-15-24 ganged
everest
read: 9156mb/s
write: 7793mb/s
copy: 11068mb/s
latency: 49.3ns
1100mhz: 5-5-5-15-24 ganged
read: 9288mb/s
write: 7835mb/s
copy: 11316mb/s
latency: 48.6ns
x4 955 @ 3.825ghz 900mhz @ cas 4
read 9111MB/s
write 7519MB/s
copy 10153MB/s
latency 50.9 ns
im just about to use 8gb or ddr3 ram< its in the post lol
the 790x is a good chipset, its identical to the GX just without the IGP so the chances are it would be fine running 8gb of ram, infact i would hazard to say that you may even be fine running at 1600mhz+ if its one of the latest asus evo boards or gigabytes
-------------------------