There is no way to specify the cores assigned within TG2 (or any application as far as I know). But you can do this through Task Manager, to a certain extent, with "processor affinity". I'm not sure if you can differentiate between physical and logical cores there, but you can probably find a reference that will tell you.
For a Nehalem-based quad core (4 cores, 8 threads), setting it to 8 threads still gets you superior performance in most cases to 4 threads, however it doubles memory requirements from 4 threads, so it can sometimes be disadvantageous. Particularly when working with very memory-intensive scenes. I have a Core i7, and generally use 8 threads, with an 800MB cache (100MB per thread). In some cases I need to reduce that to 600MB or even 400MB (50MB per thread), which may affect performance, but I seldom go down to 4 threads. That being said in severely memory constrained situations it would make sense as 4 physical cores without memory constraints ought to be faster than 4 physical and 4 logical cores all starved for memory.
Because you'll have 2 CPUs you could theoretically use up to 16 cores, but this would definitely run into performance limits from overhead. 8 is the maximum I would use. There are also, as I said, memory issues with this, since TG2 is still a 32 bit app and can only use up to 4GB of memory on a 64 bit OS (less on a 32 bit OS). So even without the overhead, assuming that 16 threads was faster than 8, it would probably still be a good idea to limit it due to memory reasons, at least until a 64 bit renderer is available.
You can run 2 instances of TG2 simultaneously, as long as they're working on different tasks. You could be rendering a scene in one, while tweaking another scene in the other. Or rendering multiple frames of the same animation in parallel.
- Oshyan
