Killing a myth – increasing boot performance using debug options!

Have you heard? There is a mystic option witin Windows that will let you decrese the time windows boots. It takes just 5 seconds and configure and could potentially lower you boot time by 200% or even more according to some sources. As they say, if it sounds too good it probably is – and this one is. This is a hard to kill myth – I have heard it from Microsoft employees also! This myth says that you should configure the advance boot diagnostic options cpu setting to the maximum number of cores you have in your machine, thereby telling windows what number of cores to use when booting the system (and that it by default only would use one!).  This option could be usefull when developing applications: to test if the product will work as expected on uniprocessor systems or to troubleshoot a erroring system. The option does LIMIT but does NOT RAISE the number of cores.

During boot your system will detect all available processors, voltages etc and maximize it’s use of resources. What this option in-fact does is to configure the maximum number of processors/cores that will be used during boot. This means that you are setting a value that Windows normally auto-detects (the max value). The configuration GUI in Windows will also show Hyper-Threaded processors which could lead you to configure a value that is higher than the physical number of cores/porcessors and this in turn could lead to a crash.

According to Windows Internals the system almost imediatly initializes all avaliable processors, it does however initialize interupts, boot video, power management and system time and some other very fundamental stuff before. Processes that are not assisted by multiple processors in any case. Good reading. There have been a KB published (KB959233) which have been remove simply because it have not been true.

And to totally kill this myth: If Vista got loads of bad press about performance do you not think that this option would be enabled from the start in Windows 7?

There is no such thing as a free lunch you know..