80c while doing what? Typical usage?
9 percent more than 4.5ghz is 4.9ghz, which is a very healthy overclock for these CPUs - they come from the factory pretty near their max potential, it's not like in the past where a 40-60% overclock could be achieved. Going up even a few percent drastically increases the power consumption and heat output, so what you're seeing is pretty normal and expected.
You could potentially lower temperatures by delidding your CPU, but be aware that it's risky (can kill your CPU very easily) and will eliminate any resale value. If you're concerned about temps, I would suggest just backing off 100mhz and lowering the voltage. You'll never notice the performance difference.