I have an 06 Mac Pro that was in need of a video card upgrade. The unit came with a Nvidia 7300GT and I bought an ATI Radeon HD 2600XT to add to it. I have the ATI Radeon on lane 1 so it will get the full X16 and put the 7300GT on lane 4 to drive my second monitor so it will get x8 instead of x4 on another slot. My question is, the 7300GT sits with the heatsink nearly touching the hard drives above it, does this cause overheating issues with the card at all? If so should I move the card to another slot? This would either give me x4 on the 7300GT or I could configure the slots to give x8 each, but that wouldn't allow the 2600XT to run at x16 full performance. Another question, running 2 separate cards for each monitor would give me better performance if I use the better card for graphic intensive apps/games than driving both monitors off the 2600XT correct?