Compressor only uses 50% CPU

I was just wondering the same thing... just started looking around, so I'll post back here if I find anything useful.

Found this thread:

http://discussions.apple.com/message.jspa?messageID=4600411#4600411

Very Helpful Indeed!

I've tried all permutations of the methods described in said topic using compressor 3 - And I can't get my 8 processors to go beyond 80% with any configuration of qmaster cluster settings, 2, 4, 8 whatever... it just doesnt work. In fact the fastest encode on the oct for me was without using clusters, just on "local machine"...
I tested a 1 min HDV QT file and ecoded it to SD WS mpeg2 using various settings - it took 23 minutes with 4 clusters (as suggested in posted discussions) - it took 21 minutes with 2 clusters - and it only took 16 minutes with no clusters - local machine and no qmaster server running. That's completely contrary to the "four virtual cluster" method - and at no time did the processors go beyond 80%
In fact, I then tested the same encode on a quad G5 and it only took 7 minutes, and all four processors were at 90% +
So what the heck is going on? How can a quad G5 beat an 8 core Intell on all counts with compressor 3?

It has been pointed out that the amount of installed RAM makes all the difference. How much RAM is in your dual quad?