I don't care about the lower hashrate/payouts, but it's not really "fair" when linux get 2x hashrate on the same hardware. Just wanted to know why 
I've noticed that when there are updates to the client, I have to watch the CPU utilization and restart the client if it's not utilizing properly. For example, I usually get about 22k Hashes Per Second2 or somewhere thereabouts. However, when I install a new client it will drop by about 50%. For whatever reason, on launch sometimes, it will only utilize ~45% of the CPU instead of the usual ~85%. If I close and relaunch the client, it will correct it. Strange behavior but for me, restarting the client is the resolution.