ASROCK 880GMH/U3S3 no function with Radeon 7790

[Akanator]

hi this is my system :

asrock 880GMH/U3S3 Pro3 Bios 1.8
power supply Sharkoon 500W WPM500

cpu AMD X2 280 3.2 ghz

120GB HDD

RAM DDR3 2 x 4GB GSkill Rigjaw

I installed an HIS ATI HD 7790 iCooler Turbo 1GB GDDR5 PCI-E

The screen is always black. The CPU fan and VGA fan are running. Power supply is strong enough and the connections are tight, the HIs is connectet via 6-Pin connector to Power supply.....i tried other Cards on the mainboard...they are working.

The HIS Graphiccard is working on other Mainboards but not on the ASROCK 880GMH. I tried to disable internal VGA but it doesnt help.

Can anyone help please ???

THX

[Macster]

Re: ASROCK 880GMH/U3S3 no function with Radeon 7790

Got the same problem with my PowerColor HD7950PCS+. Same Motherboard. Newest BIOS 1.80. I tried several things like CMOS resets, other cables, latest drivers, some BIOS settings. Nothing works.