Working GPU not working with known working PSU

[ryedge]

I apologize on behalf of the title, I have found no similar issues anywhere. My 7850, proven fully functional in a friend's rig, refuses to work with a new PSU, which also works fine when tested with another GPU. I have run out of possible remedies, and I turn to LinusTechTips.

LIST OF ATTEMPTED FIXES:

I have cleared the CMOS, both by using a jumper and removing the battery for varied lengths of time.

I have used different modular PCIe connectors/cables, molex to PCIe adapters, cable extensions both working and not working, all to no avail.

I have used newly wiped drives, drives with a fresh windows 7 install, and my current boot drive.

I have used one stick of ram, both, and just the other.

I have reset the GPU, PSU, CPU and motherboard in the case.

It is not due to a lack of a fan in the CPU_Fan header, the heatsink overheating the CPU.

The 24 and 8 pin connectors are attached correctly.

The entire rig and all components work... but not the PSU and GPU combined. Two different case speakers give one long and two short non-repeating beeps, GPU error in MSI's beep code system. If anyone has recommendations to a fix outside of a PSU or GPU RMA, please let me know.

SPECS

CPU: AMD 965 BE @ stock freq./v

GPU: AMD HD 7850 @ stock freq./v (Might have been at ~1200MHz core at slightly over stock voltage - was a good OCer, never crashed, overheated or artifacted.)

MOBO: MSI 970a-G46

PSU: CM M2 Silent Pro 620w

Old PSU: Corsair TX650w gen. 1

RAM: Patriot Viper 2x4GB @ stock (1600) freq./v

OS: Win. 7 64bit

BOOT Drv.: Samsung 840 250GB

Also, I wonder that the modular pcie cable, which is double ended, is not enough to power the 7850, a one connector card. The PSU powers a 5870 fine with two connectors. I tried the 7850 in a rig with a non modular PSU that had a one cord to one connector type of deal, which worked fine and allowed the same overclocks, even though it was a generic 450w junky PSU.. My old Corsair PSU was similar.

[Emperor_Piehead]

have you flashed the bios?

[ryedge]

I cannot, as I do not have visual access to the BIOS, which I assume I cannot enter if my only display outlet is not functioning. However, I have arranged to borrow a friend's GTX 770 in order to perform a BIOS update, I will give an update to my situation in the morning, before attempting additional fixes.

[ryedge]

I have backdated the motherboard bios and chipset version to factory settings, then back to latest releases, still the same situation. I will take my pc to a repair shop to see what their opinions are.

[sof006]

Perhaps the PSU is faulty and it isn't giving the said amount of watts the GPU requires?

[xBlizzDevious]

You say that the entire rig works without that GPU and PSU together, have you tried a different GPU? Have you tried using other PCIe slots (if available)?

[Jesus]

Check the required Amperage on the 12v Rail spec for that card and what that PSU has Available on that 12v Rail

 

EDIT: looks like the 7850 Needs 24Amps on the +12v

 

last resort >might sound dumb, but try using electronics cleaner aresol or(99% isopropyl) with a soft bristle toothbrush on the pcie slot and the card(with power cables disconnected of course on gpu and motherboard)

It might just be coincidence that it doesnt work with a certain psu.

 

im just throwing out ideas on why a bios would throw out a gpu beep code here

 

if you have another mobo or computer you can attach that gpu and psu on another mobo to see if you still get some sort of post error

[ryedge]

Thanks for the replies. A 5870 works in either pcie slot on the motherboard, and is powered perfectly. The 620w psu I have is rated for 58amps on one 12v rail, so my 7850 is getting power, and it doesnt have a continuous beep like the 5870 has when not plugged into the psu. The 7850 works just fine in two other rigs with psus under 620w, even a 350w. The 620w psu powers those other two computers as it should. I will post results from testing at a repair shop when I get them. Thanks for the tips, and I'll give some rubbing alcohol and cotton a shot as well.

[Jesus]

Then the only thing I can think of, is check a bios setting for video output. Something may not be right.

Other than that, this one has me stumped. One of the parts wether gpu mobo or psu is doing something wrong, or a combination.

If your board has voltage checkpoints, try that.

And if your board has an auxiliary power connector, try plugging one in

Oh and one last thing, try switching from hdmi and dvi. Maybe the (not working) gpu is putting out a signal that is out of range for the monitor.

Again, still throwing out random ideas on a gpu,video beep code. This thread has me intrigued. Please post the answer if you find one.

It'll also help anyone looking for a similar solution for a similar issue.

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