Question Weird fps drop in Batman Arkham knight

[ArkhamKnight]

I've been playing batman Arkham knight for a while i finished it about over 10 times with no problem at all with my gtx 750
I started playing this game again yesterday and the problem starts.... When i look at the Batmobile just looking not even driving the fps drop to
5-10 fps and the game was running at 30 to 45 fps low settings 1080p
Now i can't play the game at all and that's the only game in my pc that does that.....the annoying thing that it was running fine and this happened all of a sudden.....can u please help me
Core i5 3470 3.2ghz
Gtx 750 1gb gddr5
8gb ram ddr3

 

[ArkhamKnight]

I've been literally suffering for weeks from my pc ....my cpu usage keeps dropping while playing any game in resident evil 7 i play for about 15 -20 minutes at maximum and then cpu usage drops and fps with it in batman arkham knight it's a little different it drops after 10 minutes of playing but when i press ALT+CTRL+DEL to get out without closing the game and then get back in the fps gets back up thats not working with resident evil 7 i dont care about that ....all i care about is to stop this from happening in the first place i realy am suffering from this please if someone can help me
give me a fix please

GTX 750 1GB (no overheating)
CORE I5 3470 (no overheating)
8GB RAM
500W

 

[rgd1101]

and the gpu usage?
ram usage?
make and model of the 500w psu?

 

[ArkhamKnight]

and the gpu usage?
ram usage?
make and model of the 500w psu?

Gpu usage is between (90-100%)
Ram usage depends on the game
Batman Arkham knight uses 6-7gb of ram
Resident evil 7 uses 3-5gb of ram
I think the gpu and ram usage are fine
Because they be like the same before and after the cpu usage drop
EVGA 500 BR, 500W Power Supply