I built a PC few days back, and it doesn't boot at all, the MoBo isn't turning on (fans not spinning), or it starts, stops, eventually booting.
SAPPHIRE HD 6870 1GB DDR5
DDR3 4GB KINGSTON CL9 1333MHz
... the rest isn't important. When I put the 9800GT in, it starts every time, but when I put 6870, it doesn't start most of the time, sometimes it does, in 10 tries for an example.
What could be the problem besides the graphics? Because, when I booted it, i played COD4 in 250+ framerates on high... so I'm in a doubt what's the problem, if the GPU is working. EVERYTHING IS CONNECTED PERFECTLY, PSU with MOBO and front panel with mobo.
1. You have a 2-rail power supply and you may have unintentionally put everything on one rail. The 6870 is a lot more power hungry than the 9800 GT. Put everything except the video card on one rail, the video card on the other.
2. There's a short or something causing the computer to turn off on its own to protect itself.
3. The video card is defective. Have you tried other PCI-express x16 slots?