After 20 minutes of testing:
first 7950 from 1.97 Mhs to 2.77 Mhs.
second 7950 from 1.88 Mhs to 2.64 Mhs.
one 280x from 2.22 Mhs to 2.65 Mhs.
After 2 hours, the averages have fall like 0.2-0.3 Mhs per gpu, but still rolling... Rejects 0.5%.
I'm not sure if it's because the pool change or maybe cos I'm mining on nicehash and it's something to do with the orders.
Enough testing. I'm back to original sph-sgminer until open-source code is provided.