HTPC and gaming same time?

[knightbringr]

I was wondering how much of an impact using a gaming PC as an HTPC would impact my gaming.

My rig:
CPU: Phenom X4 955 (95w)

mobo: GA-M57SLI-S4
http://www.gigabyte.com/products/product-page.aspx?pid=2287#ov

GPU: Radeon HD 6850
http://www.amazon.com/Sapphire-6850-PCIE-Video-100315L/dp/B0047ZGIUK

PSU: Corsair CX500 V2 500W
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139027

TV Tuner: Hauppage 2250
http://www.hauppauge.com/site/products/data_hvr2250.html

I know the first thing people will say is that it will impact my gaming, BUT the Hauppage 2250 does all the mpeg rendering - blah, blah, blah on it's circuit board, so I was thinking that maybe the rest of the system wouldn't be affected as much.

Is this a pipe dream to have both a HTPC and gaming rig in one machine and it will not affect my gaming?

(FYI) The game I will mostly be playing is Star Wars: The Old Republic

Thanks.

 

[knightbringr]

OH!

And I have 4GB of Kingston HyperX 800 RAM