256, 1-2 buffers on VEP, but John, if I remember correctly you're runnng a big template. I find it's very scripting specific. Some of my libraries:
Lass. Very efficient. HB and HS Gold not bad, but harder on CPU than LASS. Cinematic strings 2- pretty draining. EW Choirs with WB- very draining, same with Embertone solo strings and Sample Modeling Brass. On quick test, Albion sucks up some power though I haven't purged it yet. Omni and Trilian use a bunch of power, whereas Stylus is light as a feather. Apocalypse Perc, very efficient, ditto VSL SE winds. Reaktor eats my CPU for a snack.
I suggest you set up your template and start turning things on and off- much will become clear.