DarthTengil :
Yes I meant real liquid 24k pure gold to spray-paint the inside aluminium walls with from the beginning of this thread, not any color that looks like gold. I disagree with you AsAnAtheist when you were writing that "Applying paint to the inside of the case will have no affect on the cooling properties of any the objects inside as the case itself is not used as a medium to pass off heat to outside. As such the color of the paint will also be unimportant". Most cases are made of aluminium or a copper layer between two aluminium layers that have a very important role as a thermal heat medium to spread the heat inside out of the case. Adding a extra layer of metal (real pure gold) in form of liquid spray to paint the inside of the case should in my mind absorb and transfer more heat into the aluminium walls and accordingly out of the case. We use gold and copper in our heatsinks to better transfer heat out, why should it not have the same function on the walls inside a computer case?
You are confused about the functions of a case.
#1 Most cases are made out of aluminum or SECC steel (galvanized steel). SECC Steel which actually has low thermal conductivity of about 12w/km and aluminum which has a decent thermal conductivity of around 237w/km.
I have not heard of a case made out of copper with 2 layers of aluminum. Actually that would basically defy the purpose of the copper as the aluminum would ultimate decrease thermal performance of the copper by providing a very poor medium or transfer. Let's not forget the fact that a copper case would be incredibly heavy, and be prone to oxidation.
#2 If it is real pure gold, your prone to having short circuits as it does have a high electrical conductivity. While viable for the outside layer it may become dangerous to use it for the component area itself if any parts come into contact with it via whatever means.
#3 Top rated heat sinks use a copper/aluminum heat sink design. Copper pipes make contact with the processor's heat spreader through thermal compound to fill in any gaps/provide a seal. From there the copper pipes carry the heat through the aluminum portion transferring heat to the aluminum fins. From there the air flow from the heat sink's fan or case fans in the use of a fanless heat sink will transfer heat from the aluminum fins to the air. Case air flow should then remove the hot air out while bringing cold air in.
By applying gold paint you are not really going to get any cooling from it, and in fact may promote internalization of heat.
First thing is first:
Let's say you have a computer case with all of the computer components inside: CPU/heat sink, RAM, Graphics card, PSU, Hard drives etc.
Airflow inside the case will touch the case transferring some heat to it however the case itself will not serve any purpose as far as heat dissipation goes because of several factors:
1. The outside of the case has limited air flow, so transferring of heat to the outside is minimal or non existent.
2. In the event that there is air blow outside of the case hitting the case itself, there is the paint which will prevent the heat from escaping by providing a poor medium of heat transfer. Knowing this the actual material inside of the case (gold coated-aluminum, bare aluminum or SECC steel) would be irrelevant.
3. Since no heat is escaping the case it self will house some heat, upon which once the temperature rises on the case material enough to match the air inside the case the heat transfer to the case would end. Since the heat is no longer being transfered to the case, it would balance out and the case would seize to have any impact on the cooling. Please keep in mind this would take anywhere from 3 minutes to 10 minutes to take place, or less time if the components are placed under load.
Even if you were to paint the computer case gold inside/out the thermal conductivity of gold would be hindered by the middle layer of aluminum. Then even further decreased by the lack of airflow outside of the case.
Now if you were to place a room fan besides the case to blow air to the computer the cooling would be significantly better but
not because of the case, but because of the high air flow going inside the case. The case itself would not matter because since the air flow inside the case has been increased by a room fan thus introducing more cold air into the case which would absorb most of the heat, and not transfer heat to the case it self.