I think the only thing in favor of the argument that it might overheat the CPU is that many more functional units on the CPU will be active at once and with no

I think the only thing in favor of the argument that it might overheat the CPU is that many more functional units on the CPU will be active at once and with no time in between. Normally they would be idle due to cache misses and memory access. I don't think with modern CPUs that this is a problem, but you would have to test to find out!