In time for the weekend, WINE 0.9.55 has been released. WINE, which allows you to run unmodified Windows executables on Linux, with this new release has several Direct3D improvements including the ability to emulate the driver version...
I don't know if it's wine 0.9.55 or a recent team fortress 2 update, but it seems now that both of my CPUs are utilized equally when playing team fortress 2, and both are around 50% utilization. Previously, one CPU would be stressed much more than the other around 80%.