Graphics flickers/lines of death occasionally?

[PlayingPoise]

I own a Gigabyte 2GB R9 270x. Occasionally, the screen will either flicker and glitch out, or it'll just display constant lines, usually of the color of whatever was on the screen prior to the lines. Sometimes it just shows a white screen. Nothing really triggers them, they just sorta show up at random; I can't replicate it, I just need to wait for it to happen. At first I thought it was a driver issue, but after reinstalling AMD's drivers, going back to the non-beta drivers, and even fully uninstalling them and reinstalling them they don't seem to go away. Occasionally, hitting my case will cause the lines to go away, which seems to lead to me thinking it's a hardware problem. However usually a hard reset will end up fixing it for a bit. Anyone have any suggestions on how to fix it?

The rest of my system:
CPU: Intel i5 4670k OC'd @4.3GHz
Cooler: CM 212 Evo
GPU: Gigabyte R9 270x 2GB
RAM: G-Skill Ripjaws X 8GB DDR3-1600
Mobo: Asus B85 Plus LGA1150
Case: Antec Three Hundred Two
PSU: XFX 550w Core Edition

This is a good example of what it looks like (not my picture however, I haven't been home to get a picture of it)

 

[Th3R3ALaSSaSSin4]

Maybe its from your overclocked CPU ,also have you overclocked your GPU?

 

[PlayingPoise]

Maybe its from your overclocked CPU ,also have you overclocked your GPU?

This has been happening for ~6 months, and I only OC'ed a month or so ago. I've never OC'ed my GPU, and heat doesn't seem like it's necessarily an issue because it doesn't start to flicker after a certain temperature has been exceeded, it just randomly happens. I could be playing GTAV and have temps at 60c with no issues but when it's idling at 30c it'll flicker like crazy.

 

[Th3R3ALaSSaSSin4]

I get many lines and colors like that when I overclock my GPU and it just happens when it goes below 35c,so check if your graphic card are overclocked version since you didnt overclock your GPU.

 

[PlayingPoise]

I get many lines and colors like that when I overclock my GPU and it just happens when it goes below 35c,so check if your graphic card are overclocked version since you didnt overclock your GPU.

The core clock right now seems to be 1050MHz, would that be too much? Or should I reduce it to 1000 or 950?

 

[Th3R3ALaSSaSSin4]

You can set it to 1000,because it seems that the core clock is 1000 in normal.

 

[PlayingPoise]

You can set it to 1000,because it seems that the core clock is 1000 in normal.

I'll mess with the clock and voltages and see if it changes anything. If there's any other suggestions on what it could be I'm down to hear them.

EDIT: Clock voltage settings don't seem to do much, the flickers still show up. Could it just be a defective card? I mean, I've had it for around a year and a half now...