part of the load is because of the higher temps
Sorry but that is not true. Please explain why you think higher temps increases the load. Some links to some studies to support your position would be nice, but I don't believe you will find any. That's because the load on a CPU is determined by CPU and RAM utilization - that is, crunching numbers, not heat. You are suggesting that higher temps somehow causes more data to be crunched, more data to be processed, more tasks to be performed. Why would higher temps cause more tasks to be performed? It doesn't. The number of tasks the CPU must perform does not change just because the CPU is warmer, or cooler.
In fact, if you want to get down to pure physics - the Laws of which electronics must follow, increased heat increases current. When current goes up while the voltage stays constant,
Ohm's Law dictates that resistance (i.e., the "load")
must go
down. Of course all that is controlled by the system clock and the regulator circuits to ensure those variables do NOT affect the timings, voltages, or loads.
The load on the cooling may increase, and the load on the regulator circuits may increase, thus causing the load on the PSU to increase - but the load on the CPU or RAM or graphics processor does not. Heat affects stability, not loads.
Fans should not be used to force air through a system, rather to assist the natural flow of air (which will be from the bottom front to the upper rear)
Sorry, but that is not true either - except perhaps for Home Theater PCs that run silent with no fans ("passive" cooling) - but then HTPC cases are specially designed cases that are specifically designed to create, and take advantage of "convection" cooling.
If a PC did not need forced air, the bottoms and tops of our cases would be all mesh, or giant vents, and they are not. I agree completely that too much coming in can impact the flow, but you need forced air through the case to force the hot air out, and that is done by fans drawing cool air in, not by heat rising.
There are too many heat generating devices inside a PC case to rely on natural flow.
Better cases typically support front fans to purposely push cool air across hot drives. This is necessary because there are many crooks and crannies inside a case where the air can become stagnate, unless something is forcing it to move.
Try holding your thumb over the end of an ordinary bicycle pump and operate it. You will soon find that the pump barrel can get quite hot.
I think that is an extreme example that is hard pressed to apply here. That heat is caused by
compression at the nozzle by a "piston" and MANY pounds of force focusing a large amount of air through a
tiny hole.
A good bicycle pump can produce 120PSI or more. Case fans are not designed to produce anything near that because case fans are designed to move large amounts of air through
large, non-restrictive holes. Case fans are not designed to compress air.
That said, too many fans blowing air in and not enough fans drawing it out (or vents letting it out), can cause overpressure, but that would be a very unusual, and poorly planned setup.
But if cases only needed "assistance" to keep cool, a little 40mm blowhole (case top) fan would be sufficient to get the "natural flow" to move in the right direction, but I think we know that would not be enough to keep our chipsets, drives, and other heat sensitive devices cool enough.