Crashing/Freezing, no BSOD

[Wenzer]

Hello, I should mention I'm not incredibly computer savvy, but I know general info and a little more... Just wanted to throw that out there.

I've been having issues with my computer for a while now. It's an ASUS ROG G20AJ, pre-built and store-bought. It was bought for me, by someone else, and I do not have warranty on it now.

It started out that I would be playing a game called Smite, and partway through the match, it would freeze up and the monitor would change to a different random color(s), and most of the time the speakers would buzz or make some kind of terrible sound.

For the longest time, I thought it was only the game causing this, so I stopped playing. Problem was solved. Until recently, it happened once while playing World of Warcraft. So I've been diving back into this problem to see what's wrong and hopefully fix it. At first, I thought it was a bad GPU or something along those lines, because my GPU would overheat a lot.

Before, the crashes ALWAYS occurred at some point during a Smite match. Usually 5-10 minutes into the game. After a couple of fixes that seem to help (listed below) I can play a few games or so, before it will crash. Sometimes I can play 3-5 games without crashing and then I quit and do something else.

I have tried a lot of different things, a couple of which helped slightly. The things I have tried, which did have some positive effect, are:
- Changing power settings in Windows 8.1 to High Performance, with PCI Express > Link State Power Management set to OFF
- Plugging the PSU directly into the outlet, instead of the power strip I was using previously

Things I have tried, that did not work or had no effect:
- Updating graphics drivers
- disabling Nvidia programs/features such as 3D compatibilities and HD sound drivers
- tried the TdrDelay and TdrLevel fix that seemed to work for many, but it made the crashes happen more often/faster
- Applying new, fresh thermal paste, and dusted out the case with compressed air
- Underclocking
- Clean installing OS while reverting to Windows 8.1 (originally was 8.1, free upgrade to Windows 10, then reverted back)

There might be more to list but I can't think of it off the top of my head. I'll answer any questions I can, though.

I have run Memtest86, 6 times, and it reports 0 errors.

Here is my dxdiag report: http://pastebin.com/BFqg08tB

Malwarebytes reports everything is clear in that area.

If anyone is able to provide any information or questions that I can answer, I am more than happy to oblige. Thank you very much for taking the time to read and help me!

 

[Wenzer]

Update: I tried testing the power supply brick with a multimeter -- the brick is putting out what it should be, 19.5 volts.

I ran Furmark for 15 minutes, and had no issues, not even artifacts. At the end of 15 minutes my card was registering at 95 degrees Celcius. Should I run it for longer to see if that makes any difference?

I'm really at a loss as to what I should try next, or which direction I should be going as far as looking into a specific part of the computer... I read that perhaps my resolution is causing driver feedback issues, or something of that sort... so I will try to play Smite tomorrow on a slightly lower resolution, and see if that affects anything.