AMD updated beta for win10x64 (from Aug23) and win7:
http://support.amd.com/en-us/kb-articles/Pages/Radeon-Software-Crimson-ReLive-Edition-Beta-for-[Suspicious link removed]pute-Release-Notes.aspx
Both builds have same version of graphics driver - 22.19.659.0

My test rig with 6 x RX470 Powercolor with hynix memory, clocks 1100/1820, timings from 1375mhz strap, win10x64, claymore 9.8
16.7.3 driver = 149MH/s ETH + 4400MH/s DCR
17.8.1 driver = 149MH/s ETH + 4400MH/s DCR
Aug11 beta = 157MH/s ETH + 4670MH/s DCR
Aug23 beta = 157MH/s ETH + 4670MH/s DCR

Profit boost is ~5.5% in dual-minig mode and ~4% in ETH only mode.

BUT!
I have hardcoded voltage and offset in bioses of my RX470s (1000mV in all fields and offset -16 ~= -100mV), so with old drivers they worked with 900mV in idle, and ~880mV under load.
But new drivers override some voltage settings.
So with no modifications theese RX470 worked with 1080mV and offset -16 ~= 960-980mV under load.
Power consumption increased from ~900W to ~1050W.
Changing offset to -32 (~ -200mV) with good old Wattool v0.92 lowered voltage to desired 860-880mV and power consumption lowered to expected ~900W.
I am going to make a 24-48 hours test, if it works stable, I will force ofsset -32 in bioses...