the Vienna Instruments currently don't offer RTAS (a beta turned up to be not performant enough) but it is said the 7.3.1cs4 with the current FXpansion wrapper works, although i can't say how good. we could test this configuration (m-box + PT LE) on windows as soon as we have some time (and machine) left.
i have also heard that digidesign tries to allow streaming sampler plugins more performance, but i guess this would only affect intel, at least as far as it concerns VI ... and we will let you know when a new RTAS version of Vienna Instruments is there.
christian
and remember: only a CRAY can run an endless loop in just three seconds.