If Apple doesn't step up and release a new Mac Pro in the next few months, I'm looking at getting an "interim" Mac Pro to replace my aging one whilst I figure out what to do with Premiere or Avid. Probably running FCP 7 for awhile, but do a bit of AE. The Mac Pro I'm using now is the original and a 2.0ghz to boot. So anything is a step up. Plus the newer Mac Pro could be a Premiere suite and the older a FCP suite, etc. I still see the 3.33ghz 6 core machines floating around and they seem like a nice mix of fast processing for apps like FCP that aren't going to use the multiple cores, and also still having 6 cores vs. 4 for compressor or AE. Since so many apps aren't' multicore aware, wouldn't it be beneficial to have a 3.33ghz for them instead of a 2.4? And at a $1500 costs savings too. Thoughts?
With FCP in mind, the 6 core. With a possible Avid/Premiere future in mind, the 12 core. With rumours of the end of the MacPro surfacing I would lean towards the 12 core. If the MacPro line does end you'll thank yourself for investing in the processors. If it doesn't you'll have slower FCP rendering, but still much faster than you had previously.
On my 12 core 2.66 with 12GB RAM the processor is the bottleneck in FCP, and the RAM is the bottleneck in everything else - Motion, AE, QMaster, Media Encoder, etc. Remember, Hyperthreading will double your logical core count, so 12 logical cores with the 6 core and 24 logical cores for the 12 core. That's probably the reason I misjudged when I thought I'd save a few bucks with 12gb of RAM.