[Wine] gpu scaling - aspect ratio issue

[hedron]

When I load an Infinity Engine game (in this case Baldur's Gate and Icewind Dale 2) I can't seem to get the aspect ratio to stick.  If I set IWD2 to windowed it's fine, but if it's full screen it will either load as a window anyway or stick 1024x768 resolution into a 16:9 aspect ratio.  I've fiddled with the nvidia control panel, but had no luck.

specs:
amd pII x4 955
gtx 260
gigabite ga-790xta-ud4
slackware 13