SMP Problem with quad-core processors

Windows XP is not very good in maintaining even process distribution across multiple cores. A new process typically seeks Core 0, and Core 0 always runs hotter than the others. Typically not a big problem until BOINC fires up and loads on all cores. Bingo, Core 0 gets very hot. This does not seem to be a problem with dual core processors.

So, one question and one suggestion:

In Vista (yuk) or Windows 7 better at truly symmetrical multiprocessing? Or is Linux/Unix capable of such automatic control?

I would like to request an option in BOINC to control which cores it runs on. Currently, I have to set the affinity manually.