LOL.. thats just a joke. iff your running 3000A i guess you got a very very expensive welder.. no way a curcuitboard can handle those amounts of amparage.
aerobatic revised his estimate, but I'll reiterate what he said:
The entire circuitboard is not handling 3000A. Many, many very short sections of wire deliver between 20-40A from each VRM to many Vdd leads on each chip. That's also why the VRMs are located *right* next to the chips. Almost all the resistive loss is in the chips, hence the extremely large heat exchangers (heat sinks). In terms of heat output per unit of volume, the chips far exceed nuclear fuel rods in this respect (which are also "water cooled").