I don't really see anything that should be causing issues. Try using the select button on the PS3 to bring up info while watching something that is causing stuttering. See if the total data rate from the video and audio add up to a number over 100MBS. My network is only 100MB, I have noticed some stuttering when the data rate reaches about 125MBS. If you data rate is low, then you could monitor the processess on your mac. Activity monitor is located in Applications --> Utilities. It works kind of like Task Manager in windows. You could see if you are reaching more than 200% CPU usage.