Currently I have an iMac with an ATI X1600 GPU with 128 MB dedicated ram. And I am looking at getting a new Mac one day. And I was thinking of the iMac with the NVIDIA GeForce 9400M with 256MB of shared DDR3 memory. But is the NVIDIA GeForce 9400M really better then the ATI one I have because I would want to game somewhat on the Mac; and also do some photo and a little video editing. My main question is would the NVIDIA GeForce 9400M be okay even though it has shared memory or do I need to fork up more dollars for the ATI Radeon HD 4670 with 256MB of GDDR3 memory? I always thought GPUs with shared memory was a bad idea for gaming and video editing. But with the new GPUs I really have no idea. Please help. Thanks.