I've upgraded my old video card Gygabyte 7750 to HIS 7790 IceQ Turbo. After installation of card onto mobo, plugging power into video card and powering on, system starts but doesn't boot. Power is on, fans rotate, but there's no video signal. I don't even see BIOS POST screen.
PSU: Chieftec 450-80p
MB: MSI H61M-P20 (G3)
CPU: Intel g850
RAM: Goodram 2x4GB (1333)
HDD: 64GB Crucial m4 SSD + 80GB HITACHI sata2
MON: AOC i2369Vm (connected via hdmi)
System consumes very little power, so it's definitely not a PSU insufficiency problem.
EDIT: SOLVED by updating mobo BIOS