Haswell MBP fan noise on high cpu usage

[spacht]

While running some benchmarks and trying out some games on a new late 2013 rMBP i noticed that the machine runs very quiet on heavy GPU usage, even for hours, but gets very loud after even a few seconds of 100% CPU load.

Running Cinebench R11.5 the CPU core temps reach 100°C in a few seconds with the fans spinning up to 5000/4500 rpm (left/right) moments later. After the test the fans turn down as quickly.

Is this normal behavior or might it be a bad paste job or something? This is my first Macbook and my first high-performance notebook in general.

 

[dusk007]

That is normal. Even worse on mine I think. If I run handbrake mine hits full fan speeds very quickly.

The CPU has a standard TDP of 47W and with Turbo 55-60W are possible for short bursts. The GPU is around 30W so it is a much cooler chip. Apple also disabled all turbo features a 750M would normally have.
The true TDP of a 750M is not published but based on the designs it can fit into one can guess.