In Texas where I live, june, july, and aug are the peak hot months, and there is no wind to even drive the wind turbins. So, I feel that you need a boost of something mechanical to draw in more fresh air through the soffett vents and expell the hot via a mechanical device.
Most homes have ample soffet vents, BUT they do not have enough devices to draw the fresh air in and expell the hot.
Many homes regardless of size have two or three roof turbines. This is where many people go wrong. A 1400 gross sqft home may need four or five turbines to keep up the proper job and a larger home may need 7 or eight, but that would look rediculous.
Most homes now are "hip"roof homes and have no eave vents. All you have are soffett vents.
Air in the attic is like a vacume if you will. nothing fresh comes in if the old does not leave. The rush of fresh into the attic is created by the void of exiting air leaving the attic.
I am a big believer in therm set and driven power turbines IF and only IF you have ample soffett vents and un obstructed at that.
I used to have access to a chart that showed for every five degrees you lower the attic temp, the inside temp will lower accordingly. Its very interesting. Even if you only let the unit rest and not be on for such long periods of time. You know as I that in those three months, about the only time the hvac rests is in the night time hours and later when the nightime temp falls to 95 they still stay on forever.
I do these things during those months: make sure the coils are clean and a good circulation is being allowed around my compressor. during hot times, I will hose down my compressor fins and this will help some. I will utilize all my ceiling fans, I will darken the west windows, and do my home work in good door and window insulation.