HD5670 on m4a78LT-M LE not detected

Hello and welcome to the forums
Have you installed the latest VGA drivers ?
Also,there should be an option in the BIOS for setting the PCI-E priority,make sure its set to PCI-E(not onboard).
BTW,since you are using one 5670,there isn't an option for disabling Crossfire,so don't bother with that.

Hybrid crossfirex on m4a78LT-M LE allows the Onboard graphics and pcieX16 to run in crossfire mode. HD5670 supports crossfirex but does it support Hybrid Crossfirex(CFX)?

Can sapphire HD5670 run in hybrid CFX?

m4a78LT-M LE runs AMI bios v02.61, 0704
Is there a bios update available?
If yes, then how can i safely update the bios?
Bios shows EZ flash 2 in tools menu. Theres a windows bios utility also supplied in mobo dvd.

cpu : phenom II x2 (runs 4 cores with core unlocker)
ram: DDR3 1333
SATA DVD
IDE harddisk pata

I do not need hybrid crossfire so that the onboard graphics gets switched off completely and dont mess with the HD5670 on X16.
Please suggest a ASUS motherboard without the hybrid CFX.

No you can't use hybrid CF.
Hybrid CF only works with low-end cards such as HD 3450

HD5670 is a Dx11 graphics card but the onboard graphics is older Dx10.

I did some research on this and found out that HD5670 works fine with asus M4A78LT-M LE.  

sent the mobo for replacement.

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