I'm trying this miner for the first time and I'm getting these unstable Mh/s

ETH: 07/02/17-20:38:52 - New job from eu2.ethermine.org:4444
ETH - Total Speed: 63.816 Mh/s, Total Shares: 3, Rejected: 0, Time: 00:03
ETH: GPU0 5.487 Mh/s, GPU1 20.439 Mh/s, GPU2 5.204 Mh/s, GPU3 18.170 Mh/s, GPU4 9.374 Mh/s, GPU5 5.142 Mh/s

These should read minimum of 21Mh/s

I'm running windows 10 x64
G4400 CPU
TB250-BTC v6
6 x 1060 GPUS
Latest Nvidia Driver
PSU Cougar 1050

Any help would be appreciated.