Blackops GPU compatibility

Can't find a thread on this...
mebbe didn't look well enough, please merge/move this one if so.

I have a Galaxy 9800GT and it is working fine. Probably just stick to the 1 card for my needs. If wanting to run 2 cards, there may be problems with this one, because the large nuts on the back of it that mount the cooling are so raised. This means it won't fit into the top (blue) PCIe slot because it won't clear the sonar sound card. I have mine in middle (red) slot. It has a fairly big hsf on it and I think it would be like a vacuum cleaner with a 2nd one in the lowest slot.