slow speed and the memory consumption is the biggest problem for me in OWB. Like when I want to watch a short movie on Youtube which is less than a minute then the progress bar says it needs to download maybe 2MB. The download window is only downloading an access site. But I can stay and watch for minutes that the CPU load is full, the fan is blowing after some seconds, the video is never started to play but more than 300MB of memory is eaten up or even more until the requester pops up: Retry - Quit - Crash.
When I do not wait for it but I press F12 before this requester then I get back about 1MB (values before and after in screenbar) but not the other 300 MB that the Youtube page needed. And the next problem is that when I close some tabs, then quit and restart OWB but with less open tabs than before, the memory was freed in the meantime but then OWB crashes again because it gets into the same trouble again. Why? Because RAM does not seem to be defragmented after freeing.