No monitor signal with graphics card that works in another system

[hellomuffin]

I tried asking this in the system section without any luck so thought I would try here.

I'm trying to install an older Asus Radeon HD 7850 into a old computer with an Asrock 4CoreDual-VSTA motherboard with a CORSAIR CX series 550W power supply. The monitor displays no signal, no system beeps. System will hang without post or display signal indefinitely.

Here's what I have tried so far:
-Tested Radeon 7850 in another rig. It works fine.
-Tested 4CoreDual computer with a Radeon 4670 gpu. It works fine.
-Flashed bios. No effect.
-Ensured that the 6pin PCI-E power connector is correctly attached. No effect.
-Tried computer with different monitor and DVI cable. No effect.
-Tried reseating DVI cable while computer is running. No effect.
-Installing graphics drivers for the HD 7850

 

[Mark RM]

Some Asus 7850's have Hybrid BIOS flashed to them (Legacy and UEFI) and they just don't work in every antique board out there. This is possibly your issue here I bet and there's no way to flash one back to stock "Legacy only" apparently.

 

[hellomuffin]

Some Asus 7850's have Hybrid BIOS flashed to them (Legacy and UEFI) and they just don't work in every antique board out there. This is possibly your issue here I bet and there's no way to flash one back to stock "Legacy only" apparently.

Interesting. This sounds like it could be the problem. It was also suggested to me that an incompatibility with my ram could cause this issue? Is that possible?