I shouldn't imagine much of a bottleneck there, as least none in GPU intensive games. . Obviously your dual core will still hold you back in those CPU intensive games that can utilize more than 2 cores.
If i recall correctly the 6850 was in fact not as fast as the previous generations 5850, so it wasn't a huge leap. So take that to mind when reading this i3-530 + ATI 5850 review:
Is Intel's Core i3-530 Fast Enough For Performance Gaming?
http://www.tomshardware.co.uk/core-i3-gaming,review-31852.html