No you don't. But obviously 500W probably isn't going to cut it with SLI. "SLI Certified" is mostly b.s.
Does anyone forsee any problems with using a board that old with a brand new GFX card/s? (Im waiting to see if the R600 can drop the prices of the NVidia GFXs)
No. But keep in mind that dual core S939 Athlon's are getting long in the tooth. By the end of the year they're going to look like dinosaurs.
I know that my cpu is goin to limit the GFX, to what extent will that affect performance of the GFX?
Depends on the game. Some games don't give a rats ass about clock speeds or CPU power. Others do. For now, I wouldn't worry too much about what CPU you have. Going to a 8xxx series or R600 is going to drastically improve performance no matter what you have. The best part is you can still use ur GPU if you upgrade ur system! :-)
The 8800 series of cards require a full pcie 16x slot to run according to Nvidia, I don't think the Nforce 4 boards have that, don't they split the 16x to 2x 8x when SLI is enabled?
As far as your CPU goes, I think it would run 1x 8800GTS just fine, I had an OC'ed 8800GTS installed on mine with an X2 4200+ @ 2.5Ghz and it ran very nicely, when I added the second one it made very little difference in most games as I have now become very CPU limited, soon to be fixed though.
As far as your PSU goes, a decent 500W unit will run 1x 8800GTS no probs, I doubt it will run 2 of them though.
Actually, some Nforce4 boards have full 16x slots in SLI but that doesn't mean I'd recommend the platform for 8800GTXs in SLI. Why would you use such a dated CPU and motherboard with a $1200 graphics solution?
it will work fine. my previous setup was with the a8n-sli del, x2 4600 @ 2.7 2gb ram and i went from 2 7800 gtx cards to 1 8800gts and it was faster in 3d mark 06,but when i added 2nd 8800 gts the score didnt jump up very much. score was in 9200 range ,but in my new setup it jumped to 13400. you will see big improve by adding the 1 but if two cards are used you may be a little dissappointed, i was. get yourself 1 evga 8800 gtx now and if they come out with a faster card in the 90 days step it up