Mouse lag after installing new gfx card

[BillyB0y91]

So I installed a gtx 970 yesterday and since then I have been getting noticeable lag when I move my mouse, maybe a third of a second gap. It doesn't sound like much but it's really affecting my game. How do I fix this?

 

[BillyB0y91]

Wired. Roccat Kova[+]

 

[BillyB0y91]

The refresh rate had been changed to 50Hz for some reason. I changed it back and it's all fixed now.. Thanks.