This is common knowledge for any Tech. You don't have to be a OS tech to know this stuff. Plus being a PC Tech you would know this cause not every install ever goes perfect when working on a Customers PC and you have to think on the fly and fix it right away and get it back to them. Time is money when working on their PC's.
Sorry xXxexpertxXx but to me it seems that you are not being completely honest with us. If you were a Tech you would know not to pay no $8,500 for a Desktop and $4,500 for a laptop. Every Tech has built at least 1 machine for themselves. I am not even a tech and i have built at least 30 machines by now. So who is not being honest here? CarnageX, b1gapl among many other members will back up my knowledge. I may not know it all. But i certainly can figure out just about any issue that comes up.