Thanks for giving us more detail about your experience on LM 17.
Let me see if I can address some of your issues here with your latest post.
First of all...
I still have no regrets about leaving Windows.
This is awesome! LinuxMint really does rock! And much like yourself I do still have some minor problems. But they are not deal breakers, and they don't happen all the time. So I can live with it until I get annoyed enough to start a new post in the forum and ask how to fix it.
Have you enabled the Tear Free Desktop setting in AMD Catalyst Control Center under Display Options? In my own experience this has resolved all my screen tearing issues with the proprietary AMD graphic driver.
But I have a bigger issue that makes NO sense at all. I recently bought "FlatOut 2" from gog. I may try to launch it 5 times. I either get a program error, then I try re-launching it, or I might get a black screen with just a mouse pointer that locks my machine, prompting a hard reboot.
What is weird is WHEN it does actually launch without issue, the game works fine with NO crashing.
I have a few different games like that, and to me that doesn't make sense. Why would a game launch one time, but not another?
I had this same problem in LinuxMint 16 Cinnamon 64-bit with some games. Most of the time they did not run. Every once in a while after a whole bunch of tries it would. Like you said, it makes no sense. I can guarantee you almost without a doubt that this is an issue with the Cinnamon desktop. Hence why I did a whole bunch of testing with LM 17 Cinnamon and XFCE. See my post in the following link:LM-17 Cinnamon is not good for gamers.viewtopic.php?f=225&t=173403
Things you can try without re-installing LinuxMint 17 to the XFCE version. At the Login page, try changing the session type to software rendering, log back in to see if that changes anything in how your games run. Try installing the XFCE desktop environment from Synapatic Package Manager, then logout and change the session to XFCE, log back in and see if your games run any different. Just be advised that when you install XFCE this way often times fonts and other things about the desktop are not optimized the way doing a clean install of LinuxMint XFCE does. Meaning you get a basic XFCE desktop without LinuxMint customizations. Another option is to make a Live CD/DVD/USB flash drive of Gparted, re-size your partitions to make room on your hard drive and install LinuxMint 17 XFCE along side the Cinnamon install so you are dual booting. When you are done testing, delete the LinuxMint partition you do not want and re-size the partitions back to using the whole drive. Another option is to use Clonezilla software to clone your current LinuxMint partition(s) (don't worry about the swap partition) to an external hard drive or large enough USB flash drive. Then do a fresh install of LinuxMint 17 XFCE over writing your current LinuxMint install. If nothing improves, restore the Clonezilla image and you are back where you left off.
In any case, I am starting to think it has nothing to do with my video card. But it probably does have something to do with some hardware not "initializing" properly.
Again, my experience showed it was the Cinnamon desktop that was the issue, not the graphic drivers. You'll see in my post in the above link that all three versions of the AMD proprietary graphic driver in LinuxMint 17 XFCE 64-bit had the same results with running games, which was to run all of them with the exception of Rollercoaster Tycoon 2 under WINE in full screen.
Although I tried many different drivers for my ATI card, I have currently settled on ATI's latest official driver. I didn't catch the fact it doesn't "officially" support LM 17/Ubuntu 14.04, but considering its no better or worst than any other driver it seems to be fine as it hasn't caused me any issues.
I'm surprised this worked out for you in terms of actually working correctly, being stable, and not screwing anything up like it did for me. I also wonder if this graphic driver version not being compatible with LM 17/Ubuntu 14.04 may be playing part of the problem with some of your games not running. It's certainly easy enough to un-install that driver and either install the 14.6 beta, or the older version from the Driver Manager. If you do this I'd recommend that you use the 14.6 beta since that showed in my tests to make more of my games run properly in Cinnamon, just not all of them.
Let us know what your results are if you keep trying different things. And wishing you good luck to get this figured out!