Only the pirated version lags; the lag is due to the game constantly requesting Ubisoft, so you need to block incoming and outgoing connections in the firewall. If that doesn't work, turn off the internet and enjoy the game.
Actually, I bought a licensed copy for 509 rubles on Steam, and I'm having a great time; no lag, no bugs... version 2.22, I think.
I have a direct license from Ubisoft - it only lags in online mode... it just freezes on the video... but it runs fine offline!

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Неудачное планирование ведёт к неудаче ...
NCF - мод, добавляющий дополнительных существ в HeroesV 3.1