Hello, I'm currently running an hp dc7900 sff. Everything on the old girl is stock for now. I've recently ordered a 365 watt power supply so power consumption should not be an issue. I am however, concerned about the compatibility of the gt 440 with my old machine. For starters the gt 440 is ddr3 and as for as I know my whole machine is built on ddr2.
More aboutgalaxy compatible dc7900
It will work in your pc.Ram memory specs have no relation with gpu memory.you can get ddr3 or ddr5 gpu.