The hires timer in Windows, and indeed any x86 based machine, is actually a clock-cycle ticker direct from the CPU. Its granularity can be down to 1,000,000,000ths of a second. By contrast the O/S thread scheduler and messaging system is very vague, relying on the fairly low resolution of the system clock.
On MacOS there should be an equivalent hires timer but it's up to Gregory to make the port happen. Of course he can't yet, because he hasn't got a 1.4.x Mac port to play with. But it will rock.
And we still have no takers to port the LWJGL to Linux. C'mon, surely not difficult?