I have a mac pro 2.66 with 3gigs of ram.
I run media 100 producer 11.5.1 without any problem.
I most often use the media 100i codec inside because I have an other media100 8.1.1.
When I try to play a media100 video clip in quicktime ouside media100 producer. I have a white video on quicktime.
No problem in after effects. Only in quicktime player. I can't run my video. This a little bit inconveniant when I clean my projects.
the Media 100 Codec is PowerPC (G5), on a Mac Pro, you would need to access the codec via Rosetta. Media 100 Producer is running under rossetta in this scenario, so it understands the codec.
to get the codec to work in quicktime player, navigate to your application folder, select the quicktime application icon and 'get info' (cmd+i) there's a check box called 'run under rosetta' or something similar - turn that on, and you'll be able to access the Media 100 codec in QT.
I think that You can do the same thing in DVD Studio Pro too if you use it...