Hey,
Im owner of 2 7970 Matrix Platinum in a CrossfireX Setup. Last year or so I had huge problems with GPU Tweak, ending up in a very "messy" deinstalation of that program and me not beeint able *to install any GPUTweak version anymore since it always gave an error. I used Afterburner then, for minor overclocking ans monitoring. Tried to get voltage control, which didnt work out. Fan control wasn't possible with Afterburner either, since Afterburner can only control 1 fan of the Matrix Platinum card. Well known, so far so good. I was able to control both fans in GPU Tweak though.
Now I recently got my second Matrix Platinum, and upgraded to Windows 10, complete fresh install with formating the drives so Im back to GPU Tweak. Installed the newest version (1.3.9.7 or sth like that) and am using driverversion 16.10.2 (will upgrade to 16.10.3 soon)*
The voltage control seems to work kinda messy, but it works. Just that GPU Tweak always ready lower voltages than I set, but values seem to change. But: I cant control the second fan of either card. There is no fan-speed reading shown next to the slider and if I try to enter a manual value it just goes back to 0 as soon as I press enter. Why is this? Shouldnt GPUTweam be able to control both fans? Or is it necessary to use an older GPU Tweak? (Maybe even GPUTweak one instead of two?)
Same for thr Load Line control btw. No reading, no possibility to change that setting. (Though Im unsure what the LoadLine setting does anyway lol)
Disabling crossfire doesn't seem to make any diference. And GPUTweak does recognize both cards correctly as 7970 Matrix Platinum. Only "diference" to kther setups might be that I disabled ULPS, since it seems to help with those huge driver issues Ive got with crimson.*