It's official, the on-GPU bloom filter code is not working on Nvidia Tesla K80. 
So what do u want me to put on those GPU k80 servers ?
The new version I will write especially for these servers. It's PITA, but it would be a shame to not have a keyrate doubling.
So wait for it (1-2 days). I believe these 4 x K80 machines could still deliver more than 70 Mkeys/s each (machine).
Rico