The Shuttle SX58H7 is really powerful as far as compact PCs go. It has a 500W PSU, but no mention of any 6-pin, 6+2 pin, etc. PCI-e power connectors. I would say to be safe and go with any card that does not require extra power. What are you going to use it for? Gaming? HTPC?
hi its got 2-6 pin PCI-e power connectors, i like to play the occasional game i'e arma2 and some photograhy work so nothing to over taxing just want to put a card in that will run stable i'e GTS 250 or GTX 260 ?
The game is more taxing than the photography. I looked up the recommended requirements, and you're probably looking at a little under a $100. If you want ATI, an HD4850 will do. For Nvidia, GTS 250. Either one of those will give a you the cheapest card that fits with your PSU and can play your game smoothly. You can go faster, but it's probably better to go with a lower-powered card due to possible cooling issues in your case.