For some reason it's using the Intel graphics card (integrated) instead of the NVIDIA one (discrete). I'll see if I can do something for next version.
I'm having the same problem as well. Up-to-date drivers. Asking the programs (cRPGlauncher, mb_warband.exe, mb_warband_old.exe) in NVIDIA Control Panel to use the High-Performance NVIDIA processor, but no luck.
I'm on a laptop with i7-3610 and GT 650M with Optimus. It seems that my dedicated GPU isn't in use, as my laptop is expelling heat barely above body temperature. When I play without WSE2 on Dx7 and Dx9, my fan and heat sink run noticeably hotter and faster/noisier, but with higher and consistent frame rates. ~30-90 FPS with WSE2, ~100+ FPS without. Load textures on demand turned OFF for both. Both on Lowest settings at 1366x768.
Still very playable, but would love the extra fps, especially during large battles.
Edit: I'm thinking it could be possible that the GPU is still being used, and might be some other weird problem. The frame rates are actually really close on low population servers. .____.