HoMM3 HD bug reports.

I tried xBRZ, and it's incredibly slow. It's hard to even describe. I joined a game and started playing with someone, but in 2 minutes, I bought heroes, upgraded one to level 1, transferred the army to the second hero, and that's basically all I could do.
It's impossible to play with it; what's the point of having such a slow filter?

Thank you for the post. Starting with a certain version, due to an error in the code, the Scale2x, UltraSaI, and xBRZ filters were always calculated in a single thread (always using one processor core), and code optimization was also disabled.
This will be fixed in the next version. However, for the demanding xBRZ filter to provide a truly comfortable gaming experience, you'll still need a modern processor with 4 or more cores.