Hello, all! There was a problem in Windows XP and 2003 Server with using QueryPerformanceCouner() function. Sometimes it can cause problem with precision time measurements on CPUs which support powersaving modes by changing clock frequency. The simplest solution for that was /usepmtimer key in boot.ini file which forces the system to use another timer. I just want to know does this problem appear in Windoes 7? And how to solve it since there is no boot.ini file in Windows 7? Thanks a lot! P.S. This is a page with detailed description of the problem: http://support.microsoft.com/default.aspx/kb/895980

Hi ,There is official documentation released on userpmtimer for windows 7 operating system. Also the KB article only refere to the OS which have performance problem. After reading the below article , i feel that this problem is taken care in windows 7 / windows 2008 ( though there is no formal written documentation ) http://blogs.technet.com/perfguru/archive/2008/02/18/explanation-for-the-usepmtimer-switch-in-the-boot-ini.aspxyou can post in windows 7 dedicated forum, so that MVP / Microsoft Engineers and community members would suggest you with latest data if any.http://social.technet.microsoft.com/Forums/en-US/category/w7itpro

Thanks a lot for the link!