Thanks kszularz, I fix it with "Flush socket pools"

I have the same problem too. I am someone that could be called as "heavy user". Normally I don't close Opera in days and I use to have an average of 15+ tabs opened at the same time.

I'm noticyng laggy from some time, maybe months. When I first realise it, I restarted opera (and all the opened tabs) but was the same. I tried closing all the tabs but surpresively still was laggy. It was specially noticiable in videos, that every 10 seconds aproximatedly has a "micro stop". That happens with all the videos, all the websites in flash or html5 and for example in Firefox with the same opened tabs it doesn't happens.

I just did the same that "guido11x" and renamed the Opera Next folder in %Apdata% and it worked flawlessly so probably the problem is inside, i don't know.

My specs are: Intel i5-2500k, 16GB Ram, SSD and AMD 6850HD in Windows 8.1 up to date and the latest Opera Next