It could be just as fast if the bios on a PC did absolutely nothing other than initialize the motherboard and a small basic interpreter.

A modern bios goes through more cycles during the boot phase of a typical machine than a C64 would see in its entire lifetime.

On early IBM PCs (up until around the introduction of the PS/2 anyway) there was a key sequence to boot direct to BASICA, and it was always about as fast as the 8bits were - except that most of the 8bits didn't have the slow memory check that IBM insisted on.

It will be faster actually.