I am now using 2704 bios was using 2004.

The only change I have noticed is now hd idle shutdown now works properly on every drive it must have been buggy in 2004. system is stable and C1E and speedstep both appear to work properly unlike in 2504 which was buggy and also unstable on my system.

so 2704 -> 2504 on a 6420 cpu.
so far seems to also be -> 2004.

I have my ram at 4-4-4-10 1:1 (cpu at 333fsb) its possible to run at 4-4-4-4? which some people seem to be doing.