Thermodynamics: Convection and Industrial PC Heatsinks

[Fidelius]

Hi PhysicsForums.
I have a question. I was looking through a manual for an industrial grade PC, which is fanless, with the CPU mounted directly onto the chassis which is practically one large heatsink.

When considering side-mount applications for this PC, I noticed that the manual had a picture of the PC being mounted with the heatsink fins running horizontally, rather than vertically:

I thought - surely convection would be much more effective if the fins were running vertically, then cool air would be coming in from the bottom and escaping from the top:

...otherwise the air would have no obvious path of escape:

... or is the difference between the two side-mount orientations negligible? Thoughts?

Obviously sitting flat is the optimum orientation, but I'm just considering the wall-mounting options here.

 

[davenn]

maybe the heatsink is efficient enough for its size that the added advantage of vertically mounted fins isn't a concern
or
maybe the writers of the installation manual hadn't considered that it would be better the other way ?

Dave

 

[256bits]

Or the writers of the manual, or even the marketing department, considered aesthetics to be more important to attract customers and sell the product. Notice, for example, that the name of the company is easily readable in horizontal print. Are the horizontal fins inadequate - don't know.

At lot more goes into the design of a product than just sole engineering, and compromises of features are made along the way from conception to realization.