Now posting from 21 Developer (the last version before 21 Next) and no issues there either.
Thanks, I didn't know the Developer version (I thought Next was it).
I tried the Developer version and... it worked!!. But of course, now I had nothing.
Then I copied all the files from the Next's userprofile then... again 100% CPU and very slow.
I assumed the problem was some file. I tried here and there and the problem file was History. Apparently this file was fu**ed in the update. Delete it and no problem.
Oh, in this forum quotes are done with ">" at the left margin.
Thanks again. I tried clicking the ´´ button, but didn't work in Opera 12.