trails

my current PC confg is: intel core 2 duo E7400@ 2.80GHz 4gb ram Nvidia quadro FX 580 (512mb) everythin fine doing animation except when i use motion trails... it really become slower.. so...

Can someone help figure this out.. i have a Samsung SyncMaster 940BW, my video card is NVIDIA GeForce 7300GT 512mb.. the problem is that when i play some movies, it has a trailing problem, like when i focus on objects which is moving on the video it seems that i see some trails.. is it really...