William K.'s response is correct. Going a little farther, once the heat is in the plenum air laminar vs turbulent doesn't matter so much. What matters most is the volume of heated air leaving the system. High volume usually means high speed and turbulent.
The evaluation in the blog is correct in asserting that turbulent flow is much better for heat removal, and the reason goes a bit further as to why laminar flow does not pick up heat as well. In a truely laminar flow situation the fluid molecules next to the surface may not be moving at all, and the next layer are moving very slowly, with a classical velocity gradient up to the fastest moving molecules, which are usually those farthest from the wall. The result is that heat is primarily transfered to the air br conduction through the stagnant layers. This is the mechanism of laminar flow's poorer performance.
Not the most exciting explanation in the world, but some useful background stuff.
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