CPU Cores vs. Threads?

[DanielHruby]

This might not be true with TG2, but I understand that my 8 core MacPro (10 GB Ram) can use 2 threads per core for rendering in applications like Modo.  Even with max threads set to 16 (or and min set to 14 (or 7), I don't seem to get full steam out of my CPUs.  I see only 1/3 of my CPU power being used.  Any ideas why this would happen?  Is this just during the lighting pre-pass?  I have a feeling this render will take the weekend to complete.

BTW, When I launch TG2 it says it sees 4 cores and says Override.  

[jo]

Hi Daniel,

TG2 Mac seems not to scale very well past 4 cores, which is probably why you aren't seeing full CPU utilisation. I have an 8 core Mac Pro on the way, which will let me look into things more closely. I suspect I already know what it is, an issue with the OS. Hopefully Snow Leopard will fix it.

Regarding the override, if you have more than 4 cores TG2 shows a performance warning alert at startup. There is an option to have the preferences set automatically so that only 4 cores are used. Perhaps you clicked the button for that at some time? You can change these settings in the Startup preferences panel:

http://forums.planetside.co.uk/index.php?topic=2798

Regards,

Jo