One big thing for games is that Microsoft swapped out older DirectX libraries to be fairly poor emulations/translations instead of being handled directly by the graphics card.
You can get better translation/emulation libraries that you can swap in to an application, like dgVoodo2 that can improve things hugely (but unfortunately buggy with some games). I think Wine's translation is also much better than Microsoft's for these older DX versions.
Yeah, software using DirectX8- is a crapshoot on Vista+ Windows, and often is too heavy (because 3D) to emulate. I haven't had much luck with Wine either...
You can get better translation/emulation libraries that you can swap in to an application, like dgVoodo2 that can improve things hugely (but unfortunately buggy with some games). I think Wine's translation is also much better than Microsoft's for these older DX versions.