Rendering on more then one core

Question

Hi,
I've been using mac's for a few years now but until recently I've not had reason to use Motion. now that I have I must say I'm really disappointed in out put.
Here's the scenario: I'm using OSX 10.7.4 on a 3.4Ghz i7 iMac with 8GB of ram. so I'd assume rendering a 30 second clip shouldn't me more then a minute or 2. alright I turned motion blur on... but does this really mean I should expect a 2 hour wait?
I had a look around and found in Activity Monitor that motion was only using 1 core. This astounded me and thus I quickly did an export on FCX, which used all of them. I'm not sure what the problem is but it seems compressor doesn't really want to be helpful considering that when I use the send to compressor function I get a file on 2 minutes... but no motion blur. (Activity Monitor still says only 1 core is in use)
Export using compressor settings is the closest I've gotten to it working but alas. Because compressor only uses one core this is no better. I say this is the closest because I've heard that a few years back you needed to make what's called a quick cluster to use all the cores on your computer. I made one. It doesn't turn up anywhere apart from the Share Monitor where it's happily displayed as an option but when I try to submit anything to it it's not available in either motion or compressor.
(The quick cluster by the way did capture all the cores, actually all 8 of them but thats with hyperthredding I'm assuming cos I'm sure this machine is a quad core.)
I've seen that people have had trouble connecting to quick clusters last year and where told by apple that there was no need because motion used all the cores anyway. But in my case this doesn't seem to be the case.
Should I try and re-install?
It's just I'm lost for what to do and it's really frustrating.
any help with any of the possible avenues or even one's I've not even considered would be very much appreciated 

Answer 1

Not sure what you mean for "instances for motion blur"? If you mean motion blur samples in the project properties, then yes 60 is way to high (it will render 60 versions of the frame and merge them to give the motion blur effect) 8 is the default.
The idea of a GPU is that it does graphics much faster than a CPU can. If the CPU could do it faster we wouldn't need graphics cards. If you use a 3D app, you'll see all your CPU's maxed out, but that's a different kind of computing task.
Motion is built around the idea that you work in real-time. If you're waiting a few seconds for each frame, you need to find a workaround.
If you most of the slowdown is caused by the star particles, render that layer out as a movie, import it back in and use it instead of the particles emitter. The GPU now only has to overlay stuff on a quicktime movie, not track and composite thousands of particles. Infact, i'm guessing that you could render just 5 or 6 seconds and repeat it 6 times instead of 30 seconds.