OS: Linux Mint 17.1 Cinnamon 64-bit
NVIDIA Driver: nvidia-346 binary driver - version 346.82
WoW had been working fine, but after a system update, it is getting very laggy. I have had the system monitor up, and noticed that the CPU usage drops off when the game lags. Prior to the updates, there tended to be 1 CPU at 100% all the time, but the other were low. Now they are all moderate usage, but all drop off at the same time.
I'm sorry but "a big list of changes" is not something anybody can use to pinpoint a problem. Does not help that Linux Mint plays a weird game with system updates. They hold some back while they let others pass. One of the reasons I don't use Linux Mint.
I used to use Ubuntu, but it broke everything on a regular basis. This is the first time I have had a problem with Mint, and even now it less broken than Ubuntu regularly did. I do know that I got a new Nvidia driver in the update. Using their driver manager, I went from 340.76, to 346.82. I have rolled back the driver, but the issue persisted.
I don't believe that Cinnamon was updated, it is still 17.1. I am using Gnome 3.9.90, but yes, native games and overall system performance are fine. I have played Portal and Half-Life 2 at max settings with no problem at all. Those run through the Linux Steam though, so they don't use CrossOver, at least directly. As far as I can tell, it is only games that use CrossOver that are having the problem, and since Blizzard games are the only ones installed through CrossOver.....
When you run "top" in a terminal window, is there a considerable amount of CPU time spent in the Linux kernel (the "sy" part in line 3). Does direct rendering still work? It may be broken for 32 bit applications. It's also possible that your system switched from the binary GPU driver to the open source one. That shouldn't hurt much on AMD cards, but on the Nvidia side nouveau is no match for the nvidia binary blob.
Supertuxcard and unfortunately most native Linux games out there are very, very simple compared to WoW and other Windows games. The Unigine-based benchmarks do state of the art rendering though.
I have an update, after I tested other games using Steam, the problem went away. I could not get it to work, but then I played games with Steam and now everything is working fine. I have no idea..... No reboot, no GUI reset, just using Steam.
We're rebels. We're misfits. But mostly, we're software liberators. And we're very, very good at what we do. We have to be. Lots of developers work with open source, but only a tiny fraction of those are good enough to get software that was designed for one platform to work on another one. We invented CrossOver software - a unique approach to cross-platform compatibility that does not require dual-boot or another OS license. We launched PortJump to help app and game developers broaden their market beyond Windows® users. And we launched ExecMode to help organizations solve really ugly technical challenges.