Assuming that your final output is a DVD compatible file, I’m not sure why Cineform would be needed. Cineform is normally used to transcode raw camera files into a more edit-friendly format, which may or may not be required with CS5. Your specs look as if your system should be able to handle the AVCHD footage from your camera. We have nearly the same specs except for the graphics card, and AVCHD files play realtime very easily.
Transcoding from Premiere to MPEG2 may be another issue, as I’ve read countless reports that Adobe Media Encoder doesn’t produce good quality files for this use.
Keep in mind that you will be going from seriously high quality HD files to incredibly lower quality SD files for DVD, so it’s hard to consider quality in this scenario.
Steve Brame
creative illusions Productions