I've tried to fix this many times, but have yet to find a solution.

My fps in fs2004 sucks on my new dual core comp. This is about the only issue left I have with this comp. Specs below (I had to remove my sig):
AMD Athlon64 X2 4800+ (Toledo cores, 2.4ghz)
ASUS A8N-SLI Premium Motherboard
eVGA 256-P2-N528-AX Geforce 7800GTX 256MB X2
OCZ EL DDR PC-3200 Dual Channel Titanium 2 gig kit
Western Digital Caviar SE WD2500JS 250GB 7200 RPM 8MB Cache SATA II HD X2
SONY DVD+/-RW (4x DVD+/-R DL, 16x DVD+/-R), Model DRU800A
Sound Blaster Audigy 4 Pro
Windows Xp Pro

At 1600 by 1200 with everything at max and AA at 4 and FSAA at 8, my fps is 0. Program is very unresponisve. Just to get 30 fps, I have to run everything at low at 800 by 600.

Its not a driver conflict or problem. I'm running 77.72, the newest ones. nothing is overclocked. No viruses or spyware or anything like that.

All others games (doom3, hl2, etc.) run a 16 by 12 with highest settings with 8x AA and 16x FSAA never dropping below 60 fps.

This is irratating the hell of me. I've tried reinstalling fs2004, windows XP, dx9, the nvidia drivers, even reformatting HD.

Any ideas?? At this point, I'm pretty clueless.

Which BIOS and chipset driver versions do you have? The latest on the ASUS site are BIOS 1006.002 (6/22/2005) and chipset v6.66 (6/27/2005). Either of these may solve issues you may have with the new dual core chips.  It could possibly be a driver issue with the 7800 also. New chip designs like these are likely to experience issues with some apps -- should be sorted in time with driver updates.

http://support.asus.com/download/download.aspx?SLanguage=en-us