On my gentoo-linux system (2.6.34-gentoo-sources amd64), with a xeon 5540 (core i7) , each time I resume after the command "pm-suspend" (suspend to RAM), mutlithreading capabilities almost disappear. More specifically, two distinct programs can use 2 distinct cores at full rate, but a single program is limited to only one core (for one instance of a multithreaded program as well as multiple instances of a single threaded program, e.g. "make -j 4" for gcc). So I end up rebooting the system. Any help appreciated!
There are other people have this problem. this is a upstream bug.
also these bug reports may be related to this one
Does the problem still occur with 2.6.37?
problem solved in 2.6.36