I've recently purchased a machine and I'm having issues with using multiple displays. I have two BenQ monitors connected to a HD 7850 card, one via DVI and one via HDMI. The setup runs fine with dual displays when doing everyday tasks, but when i switch to gaming (literally every game of the almost two dozen I have tried), invariably the PC will intermittently either freeze or shut itself off. I am unable to reproduce this issue at all when using a single display connected through either the DVI or the HDMI ports.

The specs of the machine are as follows:

Graphics Card: Gigabyte Radeon HD 7850 2GB GDDR5

Catalyst Driver Version: Currently 13.1 (have rolled back to 12.x same problem)

Operating System: Windows 8 64 bit (have also tried win7 32 and 64 bit same issue)

Issue Details: Having dual displays connected to the Graphics card causes intermittent freezing/crashing/shutdowns of PC. Does not occur with a single display.

Motherboard: MSI Z77A-GD55

Power Supply: 600w PSU

Display Device(s): 2x BenQ GL2440 (One connected via HDMI one via DVI)

Applications and Games: Have tried a range of games from low end legacy games to high end current, same problem occurs.

CPU: Intel i7-3770K

Any suggestions anyone could make would be greatly appreciated. I'd really like to have this working with dual displays.

Which PSU model is that? There are really bad "600w PSU"-s out there, if you give us the model, it can make the list of possible causes smaller. If the issue isn't caused by the power supply, then the GPU may be bad.

Honestly im not entirely sure. It....might be a coolermaster PSU? I can't find anything anywhere that provides me with a model number on the power supply unit itself (or elsewhere).

As a point of reference, I have actually had the entire rig replaced this morning (the supplier was good enough to simply provide me with another machine with the same hardware) and I'm still encountering exactly the same issue, which leads me to believe that manufacturing faults in the hardware are less likely.

I'm leaning towards believing that there may be some sort of conflict or problem with the HDMI output when used in conjunction with the DVI, although for the life of me I dont know what it could be.

I've tried removing the AMD HD audio drivers as I've seen suggested elsewhere (although these are really difficult to eradicate), I've also tried using adapters and converter cables to avoid using a HDMI connection.

I've investigated whether there are any known issues with the monitors themselves causing problems either specifically with my hardware setup or in general and can't find any literature referencing such.

I'm really puzzled by the issue =/

Heres the only thing i can think of...I have a HIS 7850 and i run on two monitors and have no problems.I have noticed when using my 2nd monitor my gpu memory stays at 1200mhz and doesnt drop down like it use to on one monitor to save energy..I believe it needs the max gpu memory to make sure it has enough mem to provide images for both monitors at all times.Get a program like real temp and check your temps and MHZ of core and mem on GPU.It could be stuck in 2D speeds which would cause it to freeze.On my HIS card my gpu program gives me a option to disable 2d clocks.

The temperature on my GPU at both idle and under load are fine. It idles between 35-38 degrees on average and under as heavy a load as I know how to give it, I've yet to see if get above 65.

The GPU clock on the card idles at 300mhz and shoots up to 975mhz when in use, however the memory clock doesnt change at all. It idles at a listed 1200mhz and doesnt change when in use. Its also at this fixed 1200mhz value whether im using one display or two. Its the same all the time.

I have to admit I don'y really know what youre referring to when you talk about "2D speeds", its not something I'm familiar with and Im not really sure how to go about changing them. Any suggestions?

Your gpu is in 2d speed when its at 300mhz.I know there was a problem with some of the cards getting stuck in these speeds which is why you would want to have it running at 975mhz all the time to see if that would fix the issue.This is the only thing i can think of.Have you tried down clocking the card to say 860mhz and see if you still have same issues.