Heat Sink Mods Without Additional Fans

Hey guys,

I am planning to purchase a Sager NP9150 from Xotic PC, and I noticed that they have a Copper Heat Sink Mod of +$79. Originally, I thought this was a good idea, but after some thought and research, I am not so content with it. It also made me doubt a lot of heat sink mods that people apply to their laptops as well. Here's why:

Heat is generated at the CPU and GPU. In order to remove this heat, a section of metal (typically copper) is place over the surface, Heating pads and thermal paste are added to increase the heat transfer. A heat pipe is attached to the metal, which carries the heat to a heat sink in front of the fans. The fans then blow air through the heat sink to cool off the heat pipe.

I came across this picture:
http://img444.imageshack.us/img444/6190/copperheatsinks.jpg (No idea where there are heat sinks on the memory units.)

Adding all of those heat sinks (~100g of Copper), does not actually increase the heat transfer out of the laptop. Heat transfer is done primary by the liquid inside of the heat sink. The fans are not designed to blow air over the user added heat sinks. Thus, adding lots of little heat sinks simply adds mass. While the computer will take longer to heat up (additional copper to absorb heat), it will not run at a lower temperature once peak the temperature is reached. (Assuming the heat dissipation via the air through the casing of the laptop is negligible.) One would need to have an additional fan blow air over the heat sinks specifically. The stock fans aren't designed for that.

Is this reasoning correct? What's your guys' take on heat sink mods?

 

you increase the heat exchange surface area thus theoretically reducing the temperature. However, you run the risk of massive heat buildup in the Chassis which can damage surface mount components on the MB. I did something similar on my N61jq and basically, I reckon the massive heat output from the i7-920xm OC fried the vRAM since a few chips were sitting directly beneath the heatpipe with all the heatsinks on it.

 

It is true that you would increase the heat transfer area, but not in a way you want. What I see is that by adding all of those heat sinks, you're increasing your copper to 'air inside the laptop' area. Heat has to then diffuse out of the casing if you don't add additional fans. This is an extremely slow process. What I see as the best way to remove heat is to have additional heat pipes or a larger heat sink near the fan. The fan can carry heat away via convection, which is many times faster then diffusion.

 

Complitely agree whith you. What is on the picture is compleet nonsence. It's against thermodinamic rules. such adding copper radiators can hurm the system even it was not OCed.

 

You could add another heatpipe with full set as in with the fan and fins, and solder em together but a bit bulky and a lot of bending, soldering and cutting in the process.... I can't think of any other way to efficiently do this other than that... or make it a water cooled laptop....

i.e:

make a box with seal around the fins and hook it up with a fish tank water pump or something similar and make a free fall water cooling system for a laptop ?? perhaps???

 

I tried this on my Medion (MSI MS16F3 barebone), it basically do nothing, neither decrease or increase temps.