Have the same problem. Using Ubuntu 16.04 LTS, nVidia 384 dirver, CUDA toolkit, using ccminer, mining on ASICPool:

https://preview.ibb.co/hTQxEb/img.jpg

- ZCash on flypool, DSTM ZCash Miner - quite accurate
- Feathercoin on Give-me-coins, ccminer - weird hashrate
- Monacoin on ASICPool, ccminer - weird hashrate
- NewScrypt on NiceHash, ccminer - quite accurate