I did some investigation regarding my eariler comment you deleted (the performance problem). It seems you are running 3 threads that are using 100% of a core each. However, each of those 3 threads spends around 82% of its execution time in the Windows API "SwitchToThread" function (called from UnityPlayer.dll). I don't know if it is because the function has some spinlock or other inside (which makes it use a lot of CPU while doing nothing, but judging by Microsoft documentation, it should be a simple function), or it's just called a lot of times per second, so the total execution time sums up to 82%. In any case, I assume this is not what you wanted to happen. I'm testing on Windows 7 x64.