I noticed this a while back too. Switch to a private chat that only contains text when you tab out of a team and it doesn't hog. I think the "don't draw in inactive windows/tabs" feature implemented in most browsers is missing.
(And Google Play on Android... on a Nexus 5, I'll sometimes wait 5+ seconds for the playlist to open after clicking the icon.)
I can collaborate that. I remember upgrading from a 486 to a Pentium 166 and being excited that I could finally play 44khz stereo MP3s at full quality and not be constantly skipping. I could even browse the web at 56k at the same time!