CS4, vista 64 bit business. dual quad core. i always leave open GL acceleration off as i find adaptive resolution fastest. my card is a quadro FX 1700. middle of the road. if i was to upgrade to say the best nvidia has to offer would i then see performance benefits beyond what my cpu's can offer? or would i just end up turning off a 2.5 thousand dollar and using adaptive resolution again?
The latter... OpenGL is pretty underdeveloped and flaky in AE. The only workflow where it really makes sense is, if you limit yourself to doing color corrections with accelerated plug-ins (Hue/Saturation and a few others) and similar third-party tools like the Magic Bullet ones that either in part or in full make use of OpenGL functions. So for the time being, an affordable GeForce GT 260/280/290 will be more than sufficient (barring general compatibility issues).