Many limitations. Too many.
I can't find details on that model. Even acer was too slim on details so I tried CNET at http://reviews.cnet.com/desktops/acer-aspire-xc600-ur318/4505-3118_7-35551097.html and still not enough to look at this.
The 3850 isn't that bad for such a system but since I can't find details check out the ATI 5450 1GB card and see if it's faster than the 3850.