Can't seem to get my 5450 to work quite right...Any suggestions?

Hey guys a few weeks back I purchased an ATI 5450 for my PC so I could start watching 1080p as my old card was not capable of this. The problem is that ever since I installed the new card it just doesnt seem to be working quite properly. For some reason when their is movement or changes from scene to scene, it just doesnt seem smooth. Kind of like the way when you use your monitor before installing drivers, a sort of choppy movement. It does remind of a driver issue but I have the most current drivers installed already. Anyone have any ideas on what the problem is or even better yet a solution?

Ok...My processor is an AMD opteron 165(not OC'd), my motheboard is an ASUS a8n-e, I have 1.5gb ram and the program I usually use for media is "Zoom Player" with all the codecs that come with it. My old video card(7600gt) worked fine but couldn't handle the 1080p.

Alright I'll give it shot. Thx

that did indeed do the trick... big thx Green Eyez, i was worried it was gonig to be more complicated. Thx man