FPS drop after tabbing out

I play this game in fullscreen mode (but not in native resolution) often after tabbing out of the game, my framerate drops from 30-40 fps to 5-15 fps. This bug is not new, i got it since the West Coast map update.
When the framerate is low then i can try to switch the "Fullscreen" setting on off on off on off on... sometimes the framerate comes back to the normal level, but often i have to restart the game. This is really annoying -.-

Here are two performance screenshots:

Befor tabbing out


After tabbing out



Please help

Edit:

Specs:

intel i5-4670
GTX 770 2GB
16GB G.Skill RAM
ASRock H87 Pro4
Xbox 360 Wireless Controller

 

That happens to me occasionally as well. I noticed it happens only on the West Coast map for me. Most of the time the game needs to be restarted. Don't know why it happens. Btw what are your pc specs?

 

I had this happen with Thrustmaster wheel connected, did not happen with wheel connected, do you happen to have Thrustmaster wheel?

Although yellow color would indicate it has something to do with GPU, maybe devs know more about this.

 

I have added the specs.
The West Coast map is mostly unplayable for me, i get there also a FPS drop when i change the vehicle
(All mods are deactivated)

I am using a Xbox 360 Wireless Controller, the error also occurs without using the controller.

 

Yes it did.
Native: 3440×1440
Game: 2560×1080