I am new in this and until now I have read all the different discussions regarding these may kind of GPUs RX 470.
I have also just bought my first rig: 6pcs of XFX RX 470 8 Gb (Hynix) - RX-470P85BDB - link with all details here: http://hardware4mining.com/?product=xfx-amd-radeon-rx-470-8gb-gddr5-hynix
The rig is already configured to run SMOS, pool solo mining for ETH.
I have begun this with some money borrow from my friends that I will need to return each month - hope to manage this

So, after almost a month of testing different ways of OC them to be more stable (only from SMOS OC mode - they do not have Bios mode changed), I have the following feedback and questions:
*Feedback:
- The cards seem to work more stable as following: core 1105 and mem 2105, core undervolting at 900 with stage 4 (from SMOS OC Control Panel)101
- They are running all between 27,70 - 27,77 Mh/s at 53°C - 61°C, meaning a total of approximately 166,5 Mh/s. I have also used core 1150 and mem 2150 (total 171 Mh/s) but seems to work more unstable from the pool chart.
* Questions:
- How can I reduce the actual consumption of all of the rig? I have a consumption indicator at the rig alimentation that shows 1050W.
- Is there a possibility to still improve the hashrate without modding the Bios? Being stable at the same time (if somebody has already the experience)
- If modding the Bios, this will allow me to gain both hashrate and reduce power consumption at the same time?
Any other recommendations if someone has the same type of GPUs XFX RX 470 8 Gb (Hynix) - RX-470P85BDB? I will greatly appreciate.
My best regards!