A8N-SLI Deluxe problem

[tmim16]

Hey guys, I just got my new PC and everything is working beautifully except for one thing: CS 1.6

Whenever I play CS 1.6 about every 20 seconds I get this weird PC stutter lag. I talked to someone I know who said he had the problem as well and it was cured by turning off ACPI in this bios. I went to bios to turn this option off, but it is grayed out so that I can't change it. Does anyone know why this might be, and/or how I might disable it?

Windows works great, no hitches.
Farcry/Doom3/Half-life 2/CS:Source all run great with no hitches.

Here is my hardware if this helps:
ASUS A8N-SLI Deluxe (Bios 1013 I believe, does that sound right?)
AMD Athlon64 x2 3800+
OCZ Platinum 2x1GB PC3200
WD 2x36GB Raptors using the onboard SIL RAID (0)
XFX Geforce 7800GT

Thanks in advance guys/girls.

 

[tmim16]

Noone has ever encountered this? I thought people at anandtech had experienced everything! I'm really hurting here guys. Someone HAS to know how to disable it.

 

[wpshooter]

I believe the question would be why the parameter is grayed out in your BIOS.

Have you updated to the latest BIOS version ?

What is your power supply brand and wattage rating ?

 

[tmim16]

Yes, sorry for not being clear.

My PSU is a 500W Allied.

12V/20a - 5v/52a - 3.3v/28a

I flashed the bios yesterday to 1013