PC running slower after new GPU install

[WearyKitten]

Hi, very sorry if this has been posted before, but I can't seem to find that forum then. So I bought myself a new computer in October last year, all except a graphics card cause I had a GTX650 lying around which I used. I bought and installed a ASUS Strix RX 480 8gb a few days ago and I noticed that my pc is slower in windows and is not performing as good in not so demanding games.

My specs are:

Intel Core I3 6100

Gigabyte B150M D3H

Crucial Ballistix Sport 8gb Ram

Huntkey 550Watt PSU

Samsung Evo 750 120GB SSD

Toshiba P300 1Tb HDD

Asus RX 480 8gb

Windows 10 64bit

 

I think the cpu is bottlenecking the games but I don't know and understand why my windows is slower, my SSD still has 50gb open space, and I have done anti-virus and anti-malware scans and both come up with nothing.

Can someone please help?!?

P.S. Sorry for bad English.

[themctipers]

DDU (display driver uninstaller) the Nvidia drivers and existing AMD drivers, then fresh install AMD drivers

[WearyKitten]

Well it is better but still not quite what it used to be before the 480, and thanks