Nobody is mining zcash with the opensource miner anymore, because it is too slow.
The nethash is divided between
1. Claymore (#2 AMD windows)
2. Optiminer (#2 AMD linux)
3. Nicehash (#2 Nvidia Windows/linux)
4. Private kernels (#1 windows /linux)
Zcash is beeing harvested
Optiminer is slow and buggy. for 20 more S/s is not worthy at all.
So we need the Claymore miner to increase the speed again so that it will be the number 1. 390 will be 300H/s.