M4A78T-E & Radeon HD 5770 PCIe x16@x2

[MrJets]

I'm looking for help on this issue because I've spent the last 8 hours trying to figure this out and can't find an answer or solution anywhere.

First of all, the motherboard I'm using is ASUS M4A78T-E and the video card is the Biostar Radeon HD 5770.

The card is PCIe 2.1 x16 and it works fine except it runs @x2 instead of x16. As far as I understand the mobo doesn't mention PCIe 2.1, but only mentions support for PCIe 2.0 x16. Is this the reason my card is only working @x2?

Please help me, I know someone has to know more about this than what I can find via my many google searches.

Here's a screenshot of GPUz if it helps.

 

[Quiksilver]

Rest of system specs?

 

[MrJets]

AMD Phenom II X4 3.2ghz (OC'd to 4ghz) v1.465
2x ADATA 2gb DDR3 1600(oc) v1.6
OCZ Fatality 550w PSU

 

[Quiksilver]

Try updating the motherboard BIOS or increasing the PCI-E bus speed (default iirc is 100 Mhz) so try 101 or 102... I don't have an amd based motherboard in front of me so I can't tell what options you have.

If that doesn't work you could always trying clearing the CMOS (jumper, button, or pull battery) but you'll have to re-enter your overclock. Of course you leave it at stock and see what the bus width says first.

If the mobo has more than one pci-e slot try the second or third one...

If all else fails one of them could be faulty (card or motherboard) I'm leaning more towards the card though.