Hyper-threading (HT) is the brand name for the technology Intel uses in many of its Xeon 32-bit processors that enables one physical processor core to execute two instruction streams (or threads) concurrently. On an HT machine, when HT is enabled, each physical processor currently presents two “logical” CPU interfaces to the operating system so that [...]

Pretty good ones for the most part, unless you encounter one of several possible problems.
Capture ratios deal with the difference between the theory and practice of computer performance monitoring. In theory, since Windows derives all the CPU time measurements from the same data collection mechanism, the following relationship should hold:
S Thread(_Total) % Processor Time = [...]

Look at a combination of processor utilization and processor queuing.
(1) The primary indicator of processor utilization is the % Processor Time Counter in the Processor Object. Note that the _Total instance of the Processor Object is actually the average value over all processors. The System Object in NT 4.0 contains a Counter named % Total [...]