Hi!
I have this problem when I play HoMM5 an the expantions that some parts of the game are shown in bad graphics and others in the highest mode. Sometimes the game starts in high graphic mode an then switches at random points of the game, usually when you switch between worldmap -> battle, when you open you spellbook or turn a page in it or when you enter a town. I call this problem "fog of bad graphics". An example is a cavaliers horse is the shape of something thats simmilar to a horse while the cavalier riding the horse is at full detail.
I get these problems only when I play the game on a laptop ( I've played it on 2 laptops). I've never experienced it on my stationary and my current laptop has even better specs than my stat.
I'll uplode some screenshot later.
Can anyone help me with this problem? Does it even have a solution?

From the looks of it the game is not loading textures properly. I would recommend a new driver install for your video card if you don't have the latest drivers, and also make sure that you're running v1.6 of HOMM V

If neither one of those is your issue make sure that you have enough RAM available by closing software running in the background such as Norton AV, AOL Instant Messenger and the like.

Could you also provide a dxdiag for your computer specs? Thanks.

Yeah, I have what appears to be an identical problem. If I keep the graphics level Normal or below, it's fine (AFAIK). High or above changes to "basic" textures when I enter a town (and probably at other times).

Win7, Geforce 9800GT, latest 191.07 Nvidia drivers, 4GB DDR2 RAM, so should have no probs running at this level. Installed latest DirectX updates (Aug 2009) to make sure.

Also tried the user.cfg changes mentioned in other posts (gfx_texture_mip = 1), but did nothing. Very annoying, though I guess I can live with Normal level (can still put AA and AF on).

Will repost if I find any problems with Normal detail level. (Also using Steam V1.6 of HoMM5, if that might be relevant).