I have several dual processor trading machines that I use on a daily basis. This past weekend, I switched the trading on several of my accounts from an older server (that had hyperthreading turned off) to a newer and faster server (that had hyperthreading activated). My early indications are that this newer hyperthreaded server is running at a higher CPU (i.e. slower performance) than the old server was running (all other things assumed equal, RAM, cache, etc). Anyway, the primary application that I run in a single threaded process. The intention is that this process will run on one CPU, while all other system processes will run on the second CPU. With hyperthreading, you have the 'appearance' (in task manager) of four CPU's. Is it possible that hyperthreading reduces the amount of CPU that can be allocated to the primary process that I run, and that disabling the hyperthread could actually improve my performance? From task manager, it would appear that a single process on a dual CPU machine could consume 100% of the CPU time of one of the CPU's... With the dual machine hyperthreaded, it would <i>appear</i> that the single process would only be able to max out one of the four indicated CPU's, or only half of CPU time of one of the two real CPU's... Is this the way it really works, or would hyperthreading still allow a single process to fully max out one of the two CPU's in a dual system? Thanks for any feedback, guidance or links on the topic. -Eric P.S. For what it's worth, I'm running Windows 2000 on this machine.