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HOMM5

I have Very High and my own creatures have the quality they should have but for some reason enemy units become like this sometimes, I remember this being a problem earlier too. This particular screenshot is taken in Tribes expansion during the first campaign but I noticed it was there in vanilla HOMM V as well.

Any ideas?

Apparently it works to change graphics to either different eye candy or AA setting then revert back then play the game but it must be done every time you restart the game and possibly once in a while as well.

I welcome any permanent fixes!

Have you set AA settings in your graphic card's control panel so, that the application chooses the appropriate mode?
Also try running the game as administrator and set your preferences.

I always have it turned off in the control panel because it's rare I need AA and I want to test performance without before anyway. Now I'm using admin rights but I installed the game in a non-conventional location so I don't think it could be a rights issue, it's more like it's a bug in the game with certain Nvidia cards (only read that nvidia users get the issue).

It actually looks like a bug in HOMM5, but it happens for both Nvidia and AMD and ist rather connected to Windows 7 systems. The game seems to switch to low quality textures. To prevent this, set image quality to normal (this affects textures and particle effects and should stop the unwanted switch).

But won't that lower the overall quality of the game? I mean, now I just switch to 2xFSAA then back to no AA in-game whenever I start the game and the bug disappears and I can play as intended.

Yes, there'll be fewer particles and it also affects textures, but I don't think significantly. As it's the only permanent solution I've found, it looks like a trade-off between easy permanent solution and highest possible textures and particles with switching options each time you start the game. I haven't got it installed right now, so I can't make screenshots for comparison, but as it's running on your system you can easily check it yourself.