Allright, I eventually managed to get the damn card to mine at up to 780kh/s, but it's a frigging Boeing taking off. Temperature sticks at 80°C, which is ok...
But what is NOT ok is the fucking Asus GPU Tweak. I warn anyone and everyone who might want to mess around with it outside of normal monitoring purposes NOT TO TOUCH ANYTHING. Just don't. I'm dead fucking serious.
Here's what happened:
round one
I was messing around with settings and decided to undervolt the card a bit to possibly make it run cooler and in return have the fan spin slower.
At some point I lowered it too much, and monitor immediatelly went black, and the system apparently froze. I was like okay... damnit. Too much. Did a hard reset, only to stare at the same black screen. Balls. Rebooted in safe mode, and started looking for GPU Tweak's settings. I didn't find anything. Not even in the registry. Unable to think of any better solution, I tried deleting the folder in Program Files. For some reason some of the files were locked and I couldn't do it. Of course it didn't help.
After some hard thinking I remembered there was a GPU integrated in the CPU, so I made a switch, booted into Windows, uninstalled what remained of GT, downloaded latest version of Display Driver Uninstaller, booted back to safe mode, and nuked what remained of anything resembling AMD drivers. At this point I have to add I was stupid enough to just swap the cards in the PC when I brought the new one in, so the result was probably not very pleasant for the system.
Whatever was wrong, DDU worked like a charm and I could boot normally and do a clean install of Catalyst. Cool.
round two
I still wanted to undervolt the card, and remembered there were checkboxes in GT's settings to make it start with Windows. That must be it, right? If it doesn't start with Windows, I can get still boot even if I go too far and fix it. Right? Riight? WRONG!!!!
So I started messing around again.
At this point I have to confess I was even more stupid and didn't create a restore point. That's what false sense of safety from considering yourself a power user does to you. It kicks you right in the balls.
Naturally (and expectedly) I went too low and got the black screen again. Yea yea, been there done that. Restarted the PC and... what the actual fuck??! It ain't booting!!
Ok, reenabled iGPU, booted into Windows, completely uninstalled GT, restarted... and still nothing! Safe mode, DDU, nuke everything down, restart, reinstallation of Catalyst. Reboot and... Guess what. Something stinks. I repeated the process with different Catalyst version with the same result. Third time I simply booted from the iGPU and only updated the driver from Device Manager. That seemed to work only until the next reboot (still used iGPU). DevMan said the device cannot start because there are not enough resources or something like that. No, it just wouldn't work.
round three
I am in the process of backing stuff up and preparing Windows image to start from zero, because clearly the system is FUBAR.
CONCLUSION
Whoever programmed this piece of shit "tweaking" software should be hung from the balls and pissed on, because no matter how stupid and careless users might be, not implementing ANY kind of safety switch (or how to call it) into such program is simply fcked up. That's for one.
For two, there's absolute lack of documentation (or at least I couldn't find any). If I had at least a rought idea how it worked, I might had taken some precausions.
For three, how in the hell can you make it so that settings are applied during boot without any possibility for the user to change that?! And what's worse, with the possibility of completely killing the system?
P.S. Sorry for the potentially too high amount of profanity. I tried to keep it as low as possible.
