I had Nvidia 8800GT & I currently upgraded to Ati Gigabyte 4870x2 on intel DG35EC mobo. My PSU is 550W 12v@20A. And as i switched on my pc, it was all so so so slow. Some how in that case, I was installing drivers for it, as normal 2 times screen flashed dyring that process, but when it went for third time, it din't came back again, I waited for 30mins. And then I forced shutdowned the PC. And replaced my 8800gt & all was fine. So I think my mobo doesn't supports it or its the problem with the PSU,
Although I am buying a 800W PSU soon. But kindly let me know, does my mobo supports this Graphic card???