>>No. Under NT 4.0 or later a resolution is 10 milliseconds. IIRC, it can be changed to 1 millisecond with some WIn API call.
>
>So why does it return a value with three decimal places?

The value is in milliseconds. An accuarcy of that value depends on Windows timer resolution. See http://technet.microsoft.com/en-us/sysinternals/bb897569.aspx for details.

DECLARE Long NtQueryTimerResolution IN NTDLL.DLL ;
			Long @ MinResolution, Long @ MaxResolution, Long @ ActuaslResolution
? NtQueryTimerResolution(@lnMinResolution, @lnMaxResolution, @lnActuaslResolution)
? lnMinResolution/10, lnMaxResolution/10, lnActuaslResolution/10