Huge speed drop with Amd GPU Pro

Hello guys,

I've just upgraded my system and am now using Amd GPU Pro 16.50-365149
I tried to run the latest stable release and ran into the error described here:https://hashcat.net/forum/thread-6108.html 

I've downloaded the beta version as suggested and hashcat now starts normally except that cracking speed has decreased drastically when compared to what it used to be:

R9 290 GPU

MD5, wordlist attack:

Speed.Dev.#1.....:   211.7 MH/s (3.57ms)

Any ideas as to what could be causing this?

Thanks !