Where to start: Reset all overclocks and test.

Make sure your PCI-E frequency is set at 100, overclocking that setting will cause your nic to drop out on you. Not sure if you had yours increased in your overclock, but it's a good place to look.

That is just 1 thing to look at.On my board, the nics both died. All I did was buy a pci-e nic card and all is well again.
 

I upgraded my gpu to a r9 290 with a waterblock and back plate. My temps are low 40's idle and high 50's under load.
 
I have the gpu in the first slot and my sound card in slot 5
I can hear it make a popping/spinning noise under load. I am assuming it is coil whine. I cannot hear it, if my case is closed.
 
My network port will go out during Furmark gpu test
If I switch to the other port, I get internet back, but its very slow. If I restart my computer, my network ports work fine.
If I play Diablo 3 the computer will lock up about 10-15min into the game. It has happened twice so far.
I am able to get thru the 15min Furmark test without computer locking up.
 
My CPU bios is set to stock
I have set my memory low gap to G3
My GPU is set to stock..have catalyst CC installed latest version
I have formatted and re installed windows 8.1...currently re installing Diablo 3
 
If I don't use the GPU for stress testing/gaming, playing on the internet is completely fine
 
I have had similar issues with a GTX 470
I had zero issues with SLI GTX 670 4GB
 
Please help,
 
thank you

After reinstall, stress test, gaming for several hours, and reinstating my overclock...I think I am stable...I have some more stability tests to run in my overclocked state, but I am good for now.
 
1. Diablo crashing...I am going to say it was drivers....maybe going from nvidia to amd was a problem..
 
2. Network port dropping out...still don't know exactly what causes this..but moving gpu to the middle slot seems to help.....don't know how long I will be with just one gpu.

+1 rjohnson11