Unfortunately lowering hardware acceleration (thus forcing software mode) introduces severe audio lag. So this option is more of a last resort, but actually I swapped my SW1000XG for the Santa Cruz to get proper hardware acceleration in the first place.
I guess, I'll stick with the VXD drivers as these seem to work fine. Infact, I think EAX 2.0 is quite expendable as I rarely ever noticed a difference between EAX On / Off. There's only a small handful of games like Descent III where I really heard any difference between EAX and non-EAX mode (back then with SBLive!).
If you ask me 3D audio in games is highly overrated anyways (especially with only stereo speakers).
Anyone interested in this topic can download a demonstration tool called Player3D from sensaura.com (only available through archive.org, though):http://web.archive.org/web/20070623180748/www.sensaura.com/demos/index.php?article=player3d.htm
This one lets you select different reverb types which are supported through Sensaura 3DPA like EAX 1.0/2.0 and I3DL2 (whatever the latter is).
I find it quite useful for testing the 3D functionality, although I get strange results when using WDM drivers and EAX 2.0. The reverb seems to have too many echo reflections, which somehow can't be turned off. I also notice this when I try to add reverb to the DB50XG daughterboard I hooked up to the Santa Cruz. I wonder if the Santa Cruz' reverb is just very badly implemented, if it's a bug or if it's just a cheap reverb.
Maybe someone can reproduce this...