SLI performance issues

Just recently purchased a brand new custom system with the intent of using SLI configuration. Specs are as follows

mobo= MSI k8n diamond plus
cpu= AMD x2 3800+
memory= Corsair 1gb x2
graphics= XFX 7800GT x2
psu= 600w, specifically made for handeling PCI express in SLI mode. (cant remember the specs)
HD= Western Digital SATA 250gb

Now to the problem at hand. As mentioned above i have 2 7800GTs running in SLI mode. The games i am testing are call of duty 2, quake 4, battlefield 2, Fear, and everquest 2. My problem is that, even on default graphics settings, the game lags severly. Moreover, the FPS drops real low and have insane mouse lag delay; making the game unplayable as i can not control my character.

After hours of agony trying to troubleshoot why my new system cant even handle default settings i decide to remove SLI mode and a video card. Lone behold every game now works fantastic! Max settings on every game and it runs completly smooth.

PS: i have the most recent driver updates from nvidia and most recent updates for windows xp pro and for my mobo.

One question: you have the SLI bridge connector installed correct?

With SLI enabled, I would double check the clock speeds of both cards. There was a guy in here a couple days ago who received a 7800 that had a 12mhz core clock- it was obviously a defective card.

-mpjesse