With modded bios, undervolted/underclocked core, and overclocked mem, it seems both my 470s and 480s get about the same hashrate per power consumption. With both 470 and 480, it seems the hashrate per power consumption is slightly higher when dual mining eth + sia
which is the better choise between RX470 8GB and RX480 8GB in term of power consumption/hashrate I have found a difference of 20 Euro between this GPU:
SAPPHIRE NITRO+ RADEON RX 470 8G ---> 240 Euro
XFX RX 480 RS TripleX Edition 8GB ----> 260 Euro
Cannot tell you anything about the 470 because i'm still waiting for them.
But with the 480 8Gb i have 29.5Mhash on 95W.
edit: 95W measured with wattmeter
With 95w at the wall, what are you figuring as the system wattage? And what is your VDDC for your gpu? have you compared the hashrate per powerconsumption when dualmining to eth only?