Re: xw6400 Twin Quad Core but only 4 cores detected.

Here is the method to ensure that you get the small but important "system reserved" pratition on your W7-10 clean installs.  This is more important than most realize, and it is quite hard to get it on after the build has been done.

Look  HERE.

http://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/W7-Clean-Install-Tip/td-p/5060171

Look HERE to see why I'll not ever try to install W7 Ultimate again... I don't have that much time to waste.  And, I've heard about this too often from others....  Think of the volume of W7Pro64 vs Ultimate.... guess which one has had more improvements over the years.

http://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/Clean-install-Windows-7-Ultimate-Intermittent-Crash-No-BSOD/m-p/5767079/highlight/true#M13975