Most if not all home air conditioning units are not made to be efficient or even effective once the outside temperature gets to 95 and above. Advice by air conditioning people is to set the thermostat at around 75 or so, maybe 72-74 if you have to because any lower will just cause the unit to run constantly and it won't be able to bring the inside temps down into the 60's during a heat wave anyway.
Once the moisture is taken out of the air, you're pretty much set. Add portable fans to move more air around rather than run the outside unit into the ground. Also cover windows which catch the sun with shades or blinds or insulated curtains. Windows heat up very fast and just seep heat into rooms. Give up the view when it's 108.
Keep those furnace filters clean also, a dirty filter will cause the system to work harder and less effectively and run up your bill.
At times like these, shade trees are your best friend.
Lots of good advice from my new best friend Gus, a fantastic air conditioning man.