Thanx for the suggestions people, apreciated.
I hadnt applied that antiprotection patch as notes that came with it suggested it was for drivers post 14.40, a typo of sorts i guess.
I patched up 21.85s, edit disp for presets, installed buffer reg entry, etc. Usual methodology (+ antiprotectn). With the Maya preset, overlays enabled, there was an apparent global 'sluggishness', from tumbling an empty scene to artisan/paint, noticibly greater shadowing/ghosting during tracking, and my old friend Miss-align still present. You can almost see an apprent refresh rate of the overlay planes whilst watching the brush stamp. Big delays on whole viewport refreshes when swapping from full to multiple viewports (no surprise there).
On the otherhand, toggle overlays off and we're back in action, with well acceptable responsiveness on CP densities ~55^2 nurbs, and ~80^2 pols (with other indep scene geom present). Port swapping is fine, in general things are delightful. So, ill stick with the rest of the quadro features, ponder why my card has this problem, and buy a new card when my project's ramp up their requirements.
Cheers,
C.