Sorry for delay, have been w/o service. In answer to bordonidev I'm no longer using Chrome, only Opera v. 39.0.2256.48. To 'arepocam' I have 9 Opera Helper running now. They're consuming probably less than 2% CPU. But under the Memory Tab those 9 Opera Helpers are probably consuming 5 or 6 times the amount of memory than the next 2 highest combined, Opera and DropBox. On the other hand, since the day when I initiated the post where my Opera was running more slowly, that had been going on for a couple of days. Since then including now, the system is running quite well and satisfactorily fast. So perhaps something else was going on back then. I have started shutting down Opera every night, and my Mac every 2 or 3 nights; perhaps that's helping too. Thanks to you both for coming to my aid.