After 15.04 update: Aliased/choppy icons

Just updated to 15.04, and my icons are all aliased/choppy looking now. I tried purging and reinstalling my icon themes, and I keep seeing this warning:

gtk-update-icon-cache: The generated cache was invalid.

Even switching back to the default Ubuntu icons has the same issue - all aliased.

Screenshot...you can even see it in the application switcher, although it improves as icons approach their native resolutions:

Suggestions?

Ever thought of installing another desktop then reinstalling the ubuntu-desktop? I don't know if this will work, but it might be worth a try. For example, you can execute the following commands to install the Lubuntu desktop environment:

sudo apt-get install lubuntu-desktop
sudo apt-get --reinstall install ubuntu-desktop

If you don't want to use the Lubuntu desktop, then you can choose a different desktop environment (such as "Ubuntu") at the login screen. That idea might just work.

turned out it was the icon set! Which is weird because the issue affected 2 different icon sets I tried before, so I assumed that wasn't the problem.

Just wanted to post this to help anyone else who runs into this frustrating issue.