Thanks for responding, that info is helpful.  I did actually notice that even on reboot, the hardware settings previously set in PM are still active.  But, like I said, I've been shutting down with a taskkill.  I will continue to experiment.  Considering that you specify a voltage in mV and not a mV offset I could not figure out the problem I'm seeing with super low voltages.  If I reset my GPU using MSI AB (I didn't know there was a -resetoc command) and I run PM with a undervolt, say 1050mV on the core.  It goes off and voltage looks good.  Then if I close (the wrong way, I know), the 1050mV core voltage persists, but I understand why now.  What is still a mystery, is that when I launch PM again, with the same 1050mV setting in my bat, then I see like 930mV in GPU-Z and I get artifacts leading to either driver crash or BSOD.  So I still can't figure that one out.  Again, this is on an R9 390 / Hawaii.

Regardless, thanks for the great attentiveness to user issues!

Ive been trying PM 2.7c on a standalone desktop with R9 390 8GB (XFX).  I know this miner is focused on RX cards (which I have many of) but I have a fair number of R9 390s and I'm having a lot of hardware control problems.

I'm getting 'failure to set -tt error -1', but setting a static fan speed works.  However, the fan speed sticks even after I close the miner.  Similarly, my clocks and voltages will set (watching in GPU-Z), but they won't reset when the miner closes.  This is a big problem since when I try to launch a second time, it seems like a negative voltage offset stacks with the first and I get BSOD, driver crash, etc.  Regardless, I pretty much have to reboot to get it to start 'fresh'.  It definitely seems faster when I can get it to run, but I have some machines that need to start and stop on demand.

MSI AB works for all my hardware settings, but I really would like the miner to handle it all and go back to stock settings when it stops.  I have a few standalone desktops with one or two GPUs that I actually use and I like them to mine when idle (scheduled task) and stop when I sit down.  I also have one dedicated rig that I run on a schedule to control heat midday.  I've been running ethminer like this; scheduled task based on idle or time.  I was about to jump to Claymore on my idle use machines simply because of the hardware control features (which ethminer lacks) so I don't have to keep switching MSI AB profiles, and that's when I discovered PhoenixMiner.

I'm just curious if these hardware control issues may be on my end or are a known issue with R9 series cards.  I have tried 3 drivers in the 18 series, but I haven't gone back to 17.  I've tried it with MSI AB reset to defaults, MSI AB completely uninstalled, AMD settings running and AMD settings not-running.  I've lowered mining intensity and slowed DAG generation and all that, but the crashes really seem to be due to ridiculously low voltages on the second run of the miner, like PM is trying to stack a negative offset each time.  Bottom line is PM doesn't release the hardware settings when it closes, at least it doesn't on this GPU and I feel like that's where my problems are coming from.  I can run PM, close it, then run something like FurMark and all my clocks and voltages are still stuck on the PM settings.

I don't mean to sound high maintenance, just want to figure this out.  If it's a known issue, hopefully it's one that will get fixed, but no big deal.  Any input would be appreciated.