Graphics problem with all games

Hi, I was playing some Terraria yesterday when my fps dropped to about 30-40 from the usual 60. It happened while I was playing though. Then I tried playing other games, like MX vs ATV: Reflex, Skyrim, Terraria (again), Dark Souls, etc. and all had the same issue, except Skyrim was completely unplayable and took ages to load. 

There was a problem I had ages ago where a file went missing from all my games on Steam, so I validated files, and that fixed it. But that doesn't seem to be working this time. I also reinstalled my graphics drivers, updated my graphics drivers, PLUS tried the beta drivers (Catalyst v14.2). None of this helped at all, but didn't make anything worse. 

... Is my graphics card broken? I noticed when I opened Skyrim that it autodetected graphics again, and set it to LOW, but it was also set to the Intel 4000 series graphics or whatever. I changed it back to my card and it didn't fix it at all. 

The only recent changes I've made were adding another monitor, which is plugged into my motherboard, not my graphics card, because I don't have the right cables. I've got one in the DVI port on my graphics card, and one VGA into my motherboard. But I didn't have this problem when I first set it up.

Any suggestions?

Plugging monitors into both your video card and monitor is a bit of an edge case, GPU-wise (at least in Windows), and is likely causing the problem. You'll have to get both plugged into the dedicated card, then disable the Intel garbage in the device manager (shouldn't be necessary, but it can occasionally cause issues).

Alright, I'll have a go at that

That was odd, and I think I know the problem. When I disabled the intel graphics, it went to one monitor only. I still don't know why the graphics issues started hours into a game...

Thanks, problem solved. The monitor I was gaming on was the one plugged into the motherboard, which used the intel graphics. When I tried playing on the other one, all problems solved