geforce ultra, gtx and gts
 

what is the difference between these symbols and what do they stand for??

not sure if they stand for anything as such, but basically, in order of price and performance, not to sure which is the lowest, gts or gtx, it used to be, gts de lowest, then GT and then Ultra (this was back in the Series 6 days though).

These are the different models of graphic processor and each have different specification and different price. For deteiled info, visit: http://www.nvidia.com/page/geforce_8800.html