Frame Drops Occur Only in Windowed Mode

My current system:

CPU: i7-12700F

RAM: 32 GB

GPU: RTX 3090

Current performance with RIFE (30 → 60 FPS):

1080p: works fine

1440p: works, but heavy load

4K (2160p): stickman hook not playable

With HFR, all resolutions run fine.

If I upgrade my GPU from RTX 3090 to RTX 5080, will RIFE be able to handle 4K interpolation from 30 to 60 FPS smoothly?
I’d appreciate feedback from anyone with similar experience or insights.

Thanks all