Is Windows XP a hybrid-threading enabled system?

Answer 1

The Windows Server 2003 family and Windows XP use the CPUID instruction mechanism to identify HT processors. As a result, the licensing model is truly HT-aware. When HT processors are detected, each physical HT processor is considered to be a single processor and both logical processors are utilized by the operating system. The license limit is measured against the number of physical HT processors in the system. The same document explains that Windos XP Home will support a single HT cpu, and XP Pro will support dual HT cpu. source: http://download.microsoft.com/download/5/7/7/577a5684-8a83-43ae-9272-ff260a9c20e2/Hyper-thread_Windows.doc I'm assuming you meant hyper-threading and not "hybrid-threading" Microsoft designed Windows XP to have Hyperthreading capibilties for systems which have Dual processors. To enable this feature, your Bios Settings dual CPU support must be enabled. When Hyper-Threading is enabled in the computer's BIOS, Windows XP automatically upgrades the hardware abstraction layer (HAL). If it must use a multi-processor HAL, and an additional processor or processors may be installed and listed under Processors in Device Manager. The system will prompt you to restart so that the new settings can take effect. More info can be found at the Microsoft site - http://support.microsoft.com/kb/810231