Primary issue i see with virtually every case fan, is that in the very center of the fan you have a dead zone, where air just hovers. that dead zone is butted up against our heatsinks, and we create an inefficient space where the fan meets the heatsink. This is the problem.

120 to 80mm adapter http://www.sharkacomputers.com/fanad8012fan.html

This adapter takes the CFM's of a 120mm fan, and increases the air velocity by passing it through a smooth cone down to 80mm.

Thinking like a rocket scientist (you know we all are), you could butt two of these adapters together at the 80mm end, creating ><.

Fan >< Heatsink

Benefits of this mod include well distributed air with no dead zone on all fins of the heatsink. and thus the ability to use air more effectively, meaning you could use a slower/quieter fan to have the same effective cooling as a higher speed fan.

So, anyone have the materials to try this out to scientifically determine if temperatures increase or decrease on either a tower style heatsink, or a downdraft style?

Someone with a smoke machine and a web cam to bench test the theory would be just as cool. Any takers?

hmm good idea, pity i got no room in my case for an adapter lol!

Not a bad idea, that would definately increase the air flow. There are some other variables to take into consideration when designing a top quality heat sink. The first is the material it is made from. Copper has roughly twice the thermal conductivity of aluminum. Better conductivity leads to better heat disapation. The second is the surface area of the metals used. The more surface area, the more heat can be displaced with the air movement of the fan. The third is the flatness of the contact between the CPU and the heatsink itself. If the contact on the heatsink is convex or concave, heat transfer is greatly reduced. Finally, a source of air movement to supply cooler air across the unit.

In designing something like that, seems like if some of these variables are implemented, there would be a very nice heatsink and fan produced as a result.

My Arctic Cooling Freezer 7 Pro works just fine. I don't need a push me pull u fan system.

sure, I would contend that the top 30 heatsinks are fine products for most everyone. I'm looking to improve on the design of how the air hits the heatsink by distributing the air better, if not faster.

The Freezer pro 7 is no different, in that the fan is awfully close to the heatsink itself, but because it is already a small fan size, finding a 120 to 92 mm fan adapter should produce even better cooling results for you under the same principle.

V3NOM has a relevant point that having room in the case for a velocity stack may be hard to come by. Heatsinks that are not all that tall will have interference issues with cabling, ram, and even video cards in some cases.

Another option would probably just be ducting. 1U rackmount server scenarios work because air is moving quickly, loudly, and the entire case is an acting fan duct. every single component is getting a swirl of air at high speed as it passes out the back of the case. Enough to cool multiple quad cores in 1.75" tall of space. Example:

http://www.silentmods.com/section1/item290/
or
http://www.silentmods.com/template [...] er_003.jpg

To get similar air flow, we use Stacker like cases with 120mm fans at every orifice, but this also seems so inefficient. having smaller cases should be easier to cool, shouldn't it? Taking a mid or full tower case, and providing a contoured baffle to decrease the volume of space you are trying to cool would help with cooling of all components.

Many, if not all air cooling questions that come across this forum are circumstantial because of the variables involved in fan and heatsink design and placement.

Circumstancial scenarios include the infamous 3.6 GHz or higher q6600 @ true 1.5V. Such a processor needs to dissipate over 200 watts of energy. This brings most air coolers to their knees without significantly high CFM high speed fans and the most surface area money can buy for a heatsink. It only works with special circumstances that are not far fetched, like a window air conditioner within a couple feet of your case, or ambient temperature is in the low 60s.

Weigh in on all that if you please.