[nikki-k]

When it comes to PCIe, there are two "specs" to pay attention to: the physical slot size, and the electrical size.
The physical size is easy- look at the board, and 99% of the time, if it is a width of 16, then ANY size PCIe card will fit. The HD PCIe cards are 1 width.

Electrical is the tricky one! As an example, you might see three PCIe slots, and all three are 16 wide physical. But, this does NOT mean they are 16 wide electrical. IN fact, chances are, at least one is far less, most likely 8 or less. Popular configs might be: 2 full 16 wide physical and electrical, typically intended for graphics card use, SLI or otherwise. Then you might have an 8 wide and another 8 wide. Or, maybe a 16 wide for graphics, then an 8 wide, 4 wide and 4 wide. Each PCIe "buss" is able to be 16 wide electrically. It can be split across slots. So, you could have two 16 wide busses, and us eone for graphics, and then split the remaining 16 wide between whatever you want. Real world and chipset allowances will enter in at this point, of course.

But, for your purposes and question: HD PCIe cards are only 1 wide, physically and electrically. They will work in any properly powered standard PCIe slot. Check Digi support, and motherboard, of course, before powering up and trying.