For some reason when you enable the feature, all the sign text becomes blurry, even with the vanilla english font

with the setting ON:

with the setting OFF:

I am using some other mods with it which could mean thats why, but I know that modernfix, moreculling, sodium extra, noxesium, and nvidium (drouarb's fork) don't bring this issue with ImmediatelyFast, it only seems to be immediately fast causing this

Upload the full game log

I have the same issue when ImmediatelyFast and CubesWithoutBorders are both enabled.
More information on the issue is here - Kira-NT/cubes-without-borders#68

CubesWithoutBorders changes the texture filtering of all framebuffers to linear instead of only the ones which are relevant to its functionality. This is definitely the fault of CubesWithoutBorders, because other mods expect their own framebuffers to have the default (nearest) filtering

I have the same issue when ImmediatelyFast and CubesWithoutBorders are both enabled. More information on the issue is here - Kira-NT/cubes-without-borders#68

Yeah, testing with cwb removed seems to fix it

here are the logs with cwb & the experimental setting on if it helps
https://mclo.gs/EN0sky1

I am closing this here, since its not ImmediatelyFast's fault