Same thing happening to my own computer (Win7 64bit). Also happening on my laptop, same OS. Opera seems to get a little bit worse with every update. The VPN has slowed to such an extent that it won't play videos and is almost unusable for anything but basic, text-only webpages. When used on Youtube it drops so many frames the video stutters every few seconds.
Opera was working perfectly for me a couple of months ago, now I'm close to dropping it for chrome.