Can someone help me here, got 6 miners. In the bat file i have the speed set to 2GHZ (0981)

http://i215.photobucket.com/albums/cc210/acheekymonkeyuk/U1_zps1e61ec9f.jpg

But they only seem to be doing around 1.6-1.8 had the 6 miners getting arounf 9.5-10GHS, but I was expecting 12GHZ

They are plugged into this hub http://www.amazon.co.uk/gp/product/B00DCO9YVM/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1 so power shouldnt be an optio, can anyone help

This is the bat

C:\Users\Windows\Desktop\Bitcoin\bfgminer-3.10.0-win32\bfgminer.exe -o stratum+tcp://uk1.ghash.io:3333 -u myname -p mypass -S antminer:all --set-device antiminer:clock=x0981 --no-opencl-binaries --no-submit-stale