Yeah, I tried re-installing. First I did a reinstall, then restore from backup. Then I did a reinstall, without restoring from backup. Either way, my documents & such are on the cloud. I figured that restoring from backup brought the junk back into configuration. Both ways, it's still slow. Guess I'll just have to live with the fact that it will be obsolete by the end of the year.

I have a "vintage" late 2013 iMac, with 8GB RAM. It's s-l-o-w with the latest OS. Would it be worth the money to invest in a memory upgrade?

Raising the temperature a few degrees changed the Sahara from lush vegetation to desert.

Begging your pardon sir, but it appears that is incorrect. If I understand http://en.wikipedia.org/wiki/Sahara_Pump_Theory correctly, the Sahara was caused by simple lack of rain. It was actually larger during the ice age.