I am not sure if you use Coinhive, but if you do, consider trying out Cloudcoins. They promise a higher hashrate for all CPU's, pay out more per one million hashes, and their fees are half of Coinhive's (15% instead of 30%). Oh, and they offer bonuses if you have a lot of people hashing at one time. I am not affiliated with them in any way, simply trying to help you and hopefully your users make a bit more bang for their CPU power.