Which is recommended? If I go with crossfire I'll probably use a Foxconn Mars board and Radeon 2900 card. If Sli, it'll be XFX 680i LT SLI board and nvidia 8600 card. For the cpu it'll be a quad 6600 or core 2 duo e6750 conroe.

I would never recommend SLI or Crossfire. according to the cpu you are buying you would be better of buying a good single graphicscard like a 3870 or 8800GT the cash spend on that card is much lower than 2 of the cards you mentioned so you can spend that extra on lets say better memory or whatever;) Sapphire Radeon X1600 PRO AMD Athlon 64 3700 Gigabyte K8NSC-939 2Gb Team Group DDR400 Maxtor 200Gb 450 Watts PSU 4 vents

Why would you not recommend sli or crossfire? Do neither one increase the performance? Do they not increase performance enough for the costs involved?

Neither..... The reason being: two mid-range gaming cards -- in nearly all cases -- typically succumb to the performance of one high-end gaming card at about the same investment. My take here is, rather than get two 8600GT cards, I would suggest buying one quite faster 8800GT for about the same cost. FYI, performance wise (excluding its DX10 support) the 8600GT is nearly in the same class as a 7900GS & we all know damn well that one 8800GT will flat-out clobber two 7900GS' in SLi. Overall, SLi has been much of a miss & very seldom is it a hit. http://www.tomshardware.com/2008/01...

And just to add...if you were to go with an SLi or Crossfire config, your power supply would have to be up to the task & would need the appropriate PCI-e connectors. So chances are, if your current PSU isn't SLi certified, you would have to upgrade that as well.

From my experience, SLI does NOT double your performance...maybe 25% gain. DigitalStorm thx, CM Stacker 830 XP Pro sp2 nForce 680i SLI mobo Kentsfield OC'd 3.33ghz, 2gb 8500 2 8800GTX'S X-Fi Fatal1tySC Tpwr1000wPS, Samsung 244T

I would like to say go for it anyway, but many are troubled by this notion. DigitalStorm thx, CM Stacker 830 XP Pro sp2 nForce 680i SLI mobo Kentsfield OC'd 3.33ghz, 2gb 8500 2 8800GTX'S X-Fi Fatal1tySC Tpwr1000wPS, Samsung 244T