Game stutter/lag after PC upgrades

ttt333

Commendable
Sep 4, 2016
4
0
1,510
Hi everyone, I recently upgraded my GTX 750 to a 780, (gigabyte windforce 3gb), I also reinstalled my CPU with still it's stock cooler, however without thermal paste as I didn't have any. (my cpu's a intel pentium g3258 @ 3.2ghz (stock)

When I bought this card I researched, and nothing said anything about stuttering with this bottleneck, it would rather just be less performance but that there should not be any problems, this was on almost every thread I looked at, so I didn't worry when I did this upgrade.

I thought I would be able to run fallout 4 amazingly, however I am running at lowest settings at 40fps with stutters all over the 20-45 range, which is massively unplayable.
GTA V, I'm forced to use a program called DXTory to cap at lowest fps, I am running at lowest settings on GTA V, and it is only just playable with this software, at 45 fps capped, but STILL stutters to 30-40 fps frequently.

Even one of the lowest tier games, CSGO I am running at max settings which should be easy, I researched this and should be getting a solid 300fps or higher at these settings but I am getting around 90-110fps going all the way down to 60 when stuttering..

That's some of the details in regards to games, I really just want to know what the problem could be, I've never had issues with my HDD (WD Blue 7200RPM) or my ram, so I didn't think this would be it, can someone please help me with this as I spent around $300 on this card and had to get another PSU also, so I really want to be able to play games normally again.
(Just for an idea, my games ran better with my old build, which was a non-bottleneck same CPU but 750 2GB, on same settings, with no stutters, so I really don't understand)

-thanks

Edit:
also, whats even stranger is that in geforce experience it is saying the optimal settings for my build is that I should be running gta and all these games at max settings with no issues at all...