An analogy might be : If you had two cups of coffee, one in an aluminium mug and one in a steel mug, the coffee in the aluminium mug would get cold more quickly. A third cup of coffee in a wooden mug would stay hot for much longer than either of the others.
Look guys, no one is arguing about which metal has better heat conductivity. This is well known by any self-respecting geek and discussed ad nauseum here and in every other cooling forum on the web.
cites is true, but it's a totally incorrect analogy
for what's actually being discussed. The medium of heat transfer in the cup is WATER
! Hence, the nature of heat transfer is direct conduction. In contrast, in a PC, the medium for any heat transfer from components to the case is AIR
, whose density compared to water is so low that the conduction is a minuscule fraction of conduction in a coffee cup. The coffee in the cup is also unmoving while the air in a typical case is being moved 20~100cfm -- ie, constantly refreshed with cooler air .
The "hot" air in a case is not really that hot, perhaps 50~60C just after it passes through the CPU & GPU heatsink fins, usually only ~6-7" from exhaust vents. Hence, there is very little surface area (relative to the skin of the entire case) actually exposed to the hot air.
The key here is how
the aluminum is being used. As a heatsink mechanically coupled tightly to the heat source, no question it's far superior to steel for cooling. But as the skin of a normal PC case without direct mechanical connection to the heat sources, aluminum has no advantage in cooling -- at least not for any normal PC. Maybe if the air was totally heated to 100C by being completely sealed in there, yeah, ok, but for any normal PC, NO!
And in a case that's well designed for airflow, lining the panels with acoustic damping that does not impede the airflow will have ZERO effect on the component temps.
All this is totally different from "heatsink" cases like the Zalman TNN, Hush, mCubed and others where the hot components' heat is conducted by direct coupling or via heapipes to the aluminium panels of the case.
For everyone who does not understand or wants to disagree with the above, read Cases: Basics & Recommendations
(esp p.1-2) before coming back with any reply. This discussion is turning absurd and will be locked if it continues in the same vein.