@cratte Just like you said, this problem still exists. It has popped back up on my PC a couple days ago, and the renderer process is the single issue. When I check that upon opening up a new opera instance daily (4 tabs, bing, FB, WIX, inboxdollars) the renderer will be consuming easily 10X or more of what your screengrab shows. Kill that once, and problem is gone for X amount of time until it bleeds out and needs to be killed again.
So Opera, are you ever going to fix this?