GPU Effects Error after applying *any* GPU accelerated effect (like transform)

Hi,

I'm working on a project and after reopening it today, I get the error message saying: "GPU Effects Error, not enough GPU Memory bla bla."

When turning off GPU acceleration everything is working, tho slowly. My GPU isnt the best (GTX 760) but it still has 4GB VRAM and it worked perfectly all the time.

So to boil down the problem I created a new project, creating just a circle. When I apply any GPU accelerated effect (like glow, or transform) it shows the error.

Already restarted the PC and AE. The funny part is, that yesterday it worked perfectly...

Updating the GPU driver did not solve the problem ...

and purging all memory and clean database also no help...