Pixel Glitch

[Bergerperson]

So I've just came across this glitch/bug in my latest game, non of my previous dozens had this before. Some of the graphics become, pixely, to an extent. This happens on gold mines, holy sites, the bars when attacking an enemy, and in the trade screen among some. Here's a screenshot to explain it better..

Spoiler :

Is this just my graphics card working more than it was, or is my game slowly beginning to be corrupt?