Movies freeze while playing game

[tylonal]

I have a 3 monitor setup (had 4 but traded 2 for a TV/monitor).
I have an AMD Phenom II x4 955 processor
Radeon HD 5800 graphics card
12 GB RAM

Problem:
I have a movie playing full screen on my TV/monitor, then a full screen game playing on my main monitor and nothing/just internet on the 3rd screen, my movie will start to skip. The audio is fine and continues playing as normal, but the video skips.
When I scale down the video to say, half screen, and go back to playing, 90% of the time it will be fine.
If I stop playing the game, its fine.
If I play in windowed mode its fine (with the full screen movie)

Now, if I stream Netflix (full screen) while playing the same games (League of Legends, Dragon Age, Fallout NV, etc) the video is completely fine.

This seems a bit backwards to me, however I know that the stuff I am watching on Netflix is not streaming in HD, but it is still "streaming", so I would think that streaming would cause issues more than playing a movie that is local...

My first inclination was to upgrade my GPU (hence the forum I am posting in), but I wanted y'all's advise here.
Any helpful advise is appreciated.

 

[nvalhalla]

what video player are you using?

 

[tylonal]

what video player are you using?

Windows Media Player

 

[nvalhalla]

Try playing with VLC or MPC, WMP sucks

 

[smeezekitty]

Sounds like your GPU might be busy with the game and slacking on playing the video.

Try another video player program though.