Pixel problem when browsing/gaming

[Jamouflage]

Hello, I've been having this problem when after a an hour or so of usage, my screen would show this group of pixels that would come out from different places when I'm gaming lightly (LoL etc.) on  or browsing on Chrome, when I would minimize the window, it would go away, but as soon as I get back, It would appear again. It would only appear on certain parts of the page so scrolling through the page would somehow "disrupt" it but not totally get rid of it. After I'd say 10 minutes, it would go away completely but given another few hours it would appear again. (See pictures)

 

I've tried re-applying new thermal compund and cleaning out the dust from my pc but there was no significant change. I really wanna know if this is a heat problem or a software/hardware problem because it just gets really distracting and it gets me worried about my pc. 

 

Specs:

AMD A8 5600k (stock cooled)

GA-F2A88XM-HD3 BIOS ver. F4

Powercolor R7 290x

8gb Kingston HyperX memory

Silverstone 500W PSU

 LG M227WA monitor

Windows 10 64bit

 

Thank you for your help!

 

 

[DigitalHermit]

that would be artifacting...

 

Check your GPU temps and set a more agressive fan curve if needed...