cpu is made of almost 100% pure silicon that is extracted and purified from sand however they do sometimes dope with other metals to increase or decrease the semiconductivity of cpu.My guess would be almost 0.1 to 0.4% or maybe even 0.it depends on the manufacturing process itself.
In California we pay a pretty hefty electronic recycling fee, particularly on monitors, which are then sent to China anyways to be dumped. The people there are melting down the stuff there for the metals in the components, but also killing themselves in the process. It's become a huge problem.
You're not going to make money alone on trying to recycle gold from computer components. You need a large scale recycling facility to earn money from recycling many types of material found in electronics.
That includes copper, silver, re-usable microchips, steel, aluminum, etc.
I looked into this a few years ago out of curiosity. Based on current gold prices, I would estimate the average CPU to contain about $3 - $4 of gold.