MOTHERBOARD GOLD, WHAT COMPONENTS ARE GOLD PLATED?

I'am a computer reseller and usually take back obsolete and busted computers and give back my clients price discounts. I've got so many that I find myself looking to get into gold recovery business from computer components. I've been told that computers motherboards contain gold but what components are actually plated with gold?? is it the IDE SATA PCI AGP etc connectors or what is it ?? any help would be appreciated thanks a million