Low power draw on Mobile Quadro P4000

I am using the latest Nvidia 390 drivers on a laptop with a mobile version of the Quadro P4000 with Arch Linux - Kernel 4.15.6-1, driver version 390.25. This should have a maximum power draw of 100 watts, however in usage the p4000 (in combination with primusrun) never pulls more than 60 watts when running a benchmark such as unigine-heaven. Is this normal behavior ? or is the system imposing a software power limit?