Is my intel i7 3930k running to hot?

Not too hot, for your H100 get 2 more 120mm fans for a push pull configuration. Good temps for such a high oc!

Personally I would say that is too hot for an idle temp. Because when the CPU is under load you will likely hit 75C

I just use a Coolermaster Hyper 212 Evo to overclock i7-3930K to 4.7Ghz and is around 45c .... if I only overclock to ~4.4Ghz it stay below 40C

This is really a good CPU!

max temp for that cpu is 66'c... reduce voltages and see if your stable. if not then reduce the oc and see if your temps gradually fall over the next 3-5 days...

my guess would be the paste is compromised in some way. either a dirty contact, an air pocket or a bad pump/damaged cooler try reseting the cooler plate after you clean the cpu with proper tim remover... if temps are still to high remove the oc and measure the temps, then replace the cooler with the stock 1 and see if theres a dramatic difference. if so the cooler is the issue.
the tcase is 66'c so the slightest load will force either a shut sown or a throttle...