Tried installing ppapi flash and unchecking npapi flash and it seems to work nicely now, thanks!
ppapi flash download: http://labs.adobe.com/downloads/flashplayer.html
to disable npapi go to opera:plugins and click on show details, then unable that one
I had full-screen frame drops on Twitch; about 5 fps. This fixes it. Thanks.
Opera 26.0.1656.8, Windows 7 64-bit (WoW64).