LS Doesnt work in Exclusive Fullscreen

[vale python]

LS is not supposed to work with Exclusive fullscreen (FSE), and only sometimes may work on certain titles with DXGI

Borderless fullscreen should be as performant, if you are on win11 with Fullscreen optimisation enabled, which pseudo forces FSE

Sounds more like Vega 3 is just not fast enough. LS has a gpu compute overhead, you're probably at the limits of the iGpu. A rivatuner/special k graph of your gpu utilisation will paint a clearer picture

It's very unlikely simply using borderless fullscreen will drop your fps from 30 -> 23. At most, you may loose a single frame on windows 10 without FSO (fullscreen optimisation)

That's normal, it needs gpu headroom to generate those frames

So what's the issue

And it's not meant to work with FSE

None, and also not relevant for AMD cards

If you're gpu bound, you can toggle Anti-lag, but it doesn't do much

It will also not help if you're cpu bound/at 80% cpu load