thanks so much for all the feedback.
after a couple of weeks of testing i can report that fcp7 and compressor 3 run great and about 40% faster on the new mac pro than on my early 2008 mac pro (imports/exports, renders & compression).
my config:
– 3.5GHz 6-core with 12MB of L3 cache
– 32GB (4x8GB) of 1866MHz DDR3 ECC
– 1TB PCIe-based flash storage
– Dual AMD FirePro D500 GPUs with 3GB of GDDR5 VRAM each
many thanks again!