no, the BIOS sets up the BrandString inside the MSRs of the CPU. Even if it did, the identification number for the CPU is still hardcoded within the CPU. Registers are just fast RAM (See http://en.wikipedia.org/wiki/Processor_register and http://en.wikipedia.org/wiki/Register_file). Turn off the power and it's all gone. Again, strings may be set by the BIOS but the BIOS cannot set the processor's ID.