If I use xfce as the desktop, there seems to be A LOT less crashes. I've tried memory tests and a few other things. If you have any suggestions or diagnostic ideas, I'd be open to anything.
I'm more familiar with KDE and with xfce, there are a few things that I miss or get a bit annoyed with. But, it just seems like I have less freezes and crashes.
You could try to experiment with the Compositing type and Qt graphics system settings in Desktop Effects - Advanced tab
With my proprietary nvidia driver OpenGL+raster seems to work best.
Also, I usually stick to the Oxygen window decorations (or Plastik), because some decorations in the past have made my desktop unstable or glitchy