I am considering the Sapphire HD 4870x2 because the Supermicro dual processor Xeon boards only work with ATI Crossfire. Nvidia does not support Intel DP boards for SLI. I am looking at the new Intel Nehalem Xeon processor based boards for an upgrade this year. Nvidia 295 is an awesome card but won't work in SLI. Many of the ATI 4870x2 issues are related to drivers, power, and heat issues. Drivers will be fixed eventually.
I took care of the power issues. The workstation has its own 20A circuit. It has a 20A 2400W Tripp Lite Line Conditioner. The PC Power and Cooling 1kW-SR 1000 W power supply has its own 20A 8 foot 5-20P 14ga cord. The 1kW-SR power supply has very clear power going into its MosFETs.
The monitor and other components have their own 20A circuit. Only the workstation power supply is on its circuit.
Heat dealt with by several options.
1.) Cooler Master Stacker 810 chassis is open from front to back.
http://www.scsiraidguru.com/Computers/X7DWA-N/Pictures/P1014183.JPG
http://www.scsiraidguru.com/Computers/X7DWA-N/Pictures/P1014182.JPG
2.) Replaced all the chassis fans with Noctua fans
3.) In the summer, 10kBTU air conditioner to cool the room
4.) The E5430 Xeons are low power
5.) I am using Savvio 2.5" SAS drives for low power and low heat.
I have been dealing with ATI and Nvidia for 25 years. Drivers get fixed. Dealing with heat and power issues along with stability of the board is more difficult. I used to test for ATI. Supermicro works with ATI for stability.
Does it work with Photoshop CS4 x64 and Lightroom 2.3 x64 for on-board rendering is more important than a few games working. I have been playing Fallout 3. I did not like COD 4. I might try COD 5.