intel will be better for most games. Most games, and applications for that matter, prefer less but stronger cores (efficient).
When coded/written specifically for multiple cores (certain tasks within applications), THEN the AMD has the edge. this is generally things like render engines for 3D models, and animations. Running multiple programs side by side. Mostly professional task and programs/ situations that take advantage of that, and do so efficiently.
But..Games are starting to see more and more multicore support. Games at one point were almost entirely GPU dependent, but now the CPU is getting more and more important for games, and multiple cores means more CPU power. Things that are heavily based in physics need to be calculated in the CPU, this can be utilized for various visual effects in games (smoke, sand, lighting, water, rain, snow, all has info that's based on physics etc) so things like that are now getting pushed into the extra cores (example, an 8 core FX CPU) while the first 2 or 4 cores are used for the majority of the game. I personally say we are going to reach a limit soon in single core performance (Id say were practically there). That leaves developers with the task of spreading workload across multiple cores, efficiently. My personal opinion is that is the case now, and will move in that direction too. We wont have a choice but to optimize around cores
granted, with all that said; more intel core will still be better.
anther note, if it means you can get a stronger GPU, get the AMD CPU. If getting the i5 doesn't mean you have to drop to a lower GPU stick with it.