The final production testing is done by skilled female technicians who have the ability to test two at a time, in tandem. They've got some test hardware that I'm jealous of (fast-removal memory modules, CPU heatsinks that don't need full attachment, PCI and PCI Express logic testers, etc.) and can have a mainboard fully functionally tested in a matter of minutes.
http://www.hexus.net/content/reviews...lld19JRD0xMjg4