@limpemu Actually it no longer crashes for me nowadays, except the occasional tab crash. It still takes up huge resources, primarily RAM, though. It is therefore difficult to say what was causing the crashes. However, I do use the Opera task manager all the time, and some tabs do cause very high RAM and CPU usage. Extensions are not the culprit in my case.
In the case of GPU acceleration, as long as the browser doesn't crash I don't see a reason to turn it off, since it offloads some resources from the already-overused CPU. However, it's a good idea to try this if you are still experiencing crashes.