Hi, I've got a simple 2D game going and it works fine on Windows. I've tried on two machines, both with i5 processors, one quad core, one dual core. They both run at the full 60 frames per second, and everything is smooth. I had someone I know try it on their mac (2010 MBP), and it only manages 5-10 frames per second, and everything is super laggy - the player jumps around, and the game freaks out in general. I also tried it on a 2006 MBP, and I had the exact same results. The 2006 is a dual core, and the 2010 is also dual-core. Here's my code, I don't know if there's something about the hardware that makes it not run, and that my game is just terribly optimized, or if it's the fault of OSX and it's Java.
You can download a compiled JAR and source code here, it's a bit long to post in this thread. Make sure the DATA folder is in the same directory as the JAR when you run it.http://dl.dropbox.com/u/6059990/code.zip