Premiere will use just about any graphics card to write to the screen so you may see what you are doing
For hardware MPE you must use a specific nVidia card... or a non-supported nVidia card with a small hack
For a list of supported nVidia CUDA cards go to the FAQ
For others, the nVidia Hack http://forums.adobe.com/thread/629557?tstart=0
Thanks for your reply but the things that you have mentioned is I think as per CUDA and supported graphics card with MPE.
But on the website there are some other cards listed and other cards (apart from five graphics card of nvidia) do not support MPE.
So,in regards to other cards, what does it mean legacy support and full support?
Either I did not understand your reply properly or you might have missed some information.
Sorry about that if I did not understand.
To reiterate and rephrase the original answer:
Premiere Pro uses OpenGL to accelerate the writing of pixels to the screen. This is not new. This is therefore referred to as a "legacy" feature.
Premiere Pro uses CUDA to accelerate the processing of some effects. This is new. This feature is part of the set of performance features known by the collective name 'Mercury playback engine' ('MPE').
Thanks for this answer and this has resolved my query