I just got the same problem, I didnt have it before but I got it today, between not having the problem and having it I installed windowsblind, (a shelling program for windows, kinda like litestep)and it eats RAM. however after selecting the standard Windows shell it works again with hardware acceleration, however disabeling some of the features in Nvdidias desctop manager also improved perfoormance, furthermoore, programs like cursor XP and other programs simmilar to that and wbdegrades performance.

[Edit] The part about soldiers dissapearing with wb on is only true if you simultaniosley have anisotropic filetring and edge correction on too. Only using theose (wich are a part of the Nvidia quality/performance selcetions) decreases performance but does not remove the soldiers. Furthermoore those options are the biggets performance thives ever. This is true on Geforce 3 and 4 Ti as well as MX. It seems everything that makes the desktop and windows look nice decreases performance terribly, I think theese programs should have an (autodisable when framreta drops below X option.