My System:
Windows Pro x64.
AMD blockchain Aug11 drivers.
Rig: 6 cards ,three RX480 & three RX580.

I'm sure this has been asked before but can't find any post about it, so here goes..
I've not been messing with the voltages on my GPUs until now, and am trying to use Wattman to adjust the voltages but they don't look like they are changing (or at least not past a certain voltage as I do see a drop in the rig Wattage use).
When monitoring with GPU-Z (or HWinfo) the voltages do not change (I see a dip then it jumps back up) - I have a Windows 7 x64 setup running the 17.7.1 drivers and the volages do change on that setup (as seen in Afterburner & GPU-Z).
Is it not possible to change the GPU voltages with the new AMD blockchain drivers ?

I've changed to mining Monero (with the Claymore XMR miner) so do I really need the new blockchain drivers for Monero and if not can I re-install the 17.7.1 drivers to enable voltage changing - I hate changing the drivers as something always gets screwed up ?
Thanks.