RX480 GPU Not being recognised by mobo/Win10

[jidoujoe]

So, with either a HDMI or DP cable plugged into the GPU, z77 MPower throws up a B2 error and hangs indefinitely. I get zero response from the display.

Sorry if this is in the wrong place.

Spec:

CPU: Intel Core i5 2500k (was originally overclocked to 4.5GHz, but brought back down to 3.3GHz with BIOS flash - [more info below])
GPU: Sapphire AMD RX480 Nitro+ 8 GB OC
RAM: 2x 4GB Samsung Green DDR3
PSU: EVGA SuperNova G2 550 W
MOBO: MSI z77 MPower
SSD: Samsung 850 EVO 250 GB
OS: Windows 10 Pro 64 bit

Apologies in advance if a similar thread exists. I’ve spent hours and hours on this now and don’t have any ideas left.

What I’ve tried/things I know:

• BIOS updated to latest version using MSI Live UPDATE 6 (more than once)

• Clean windows install (more than once)

• Most recent chipset drivers installed

• I get GPU LEDs but no fans

• Seated and reseated the GPU in all three PCI slots

• Installed the GPU in a friend's machine (works fine). I also Installed a friend's fully functional GPU into my machine, same B2 error, so I’ve pretty much ruled the RX 480 as the cause.

• ‘PEG' enabled as primary display output in BIOS

• Mobo’s on board display adapter works perfectly

• Have tried disabling on-board display adapter in case that was interfering — still no joy

• CMOS has been reset several times

• When using the on-board adapter, the neither the BIOS nor Windows acknowledge the card’s presence

I am seriously stuck on this. Short of paying out for a new mobo/CPU, I really don’t know what else to do. What am I missing?

Please, please help. I don't even know what's real anymore...

 

[jidoujoe]

Have you tried different hdmi and dp cables ?
Did you try the rx480 in the board before you updated bios?

Yes to both I'm afraid.

 

[jidoujoe]

I might have to give up and get a new mobo. Damn shame, but sometimes these things can't be avoided.

 

[jidoujoe]

I've tried all three PCI-E slots and they're all unresponsive. I'm completely baffled!

 

[jidoujoe]

hmmm. PSU upto job of powering it?
Got another make/model GPU? Maybe a basic GPU? Or older gen? Maybe the PCI-E bus power requirements on the 480 (exceeds PCI-E spec) is causing a problem.

Genius idea.

Seated an old 9600gt and it spins up no issues.

 

[jidoujoe]

Definitely could be PSU as said above, what cables does the 480 take, 2 x 6pin, if so have you tried different cables. What about a mobo BIOS update?

If all else fails you could try reflowing the mobo, in other words, bake in the oven and see if that fixes it. That's extreme though and only really if you were about to actually bin the mobo.

It works. It was a cable...

Well, I went from zero knowledge about builds to some knowledge as a result, so I'll take it.

Thanks for taking then time to help me out.