My AE 2020 preview is pixelated.

Ok so, I literaly did everything I can do for fix it but nothing works.
- My adaptive resolution is on off and my preview on full
- I tried ram preview
- I tried edit < preferences < preview < and change adaptive resolution limits
or - Edit < purge < all memory
- And my GPU is not available ( so do I have to make it enable ? )
I don't know what to do next or if it's possible to fix it.
Please guys, help me !
