pad cooling fanless

hi, i have a notebook hp dv6645us and i would like to buy a pad cooling fanless, and i would like to know, whitc is the best option?
here i found 4 options

G-pad:

http://www.giga-byte.com/Products/N...ts_Spec.aspx?ProductID=2340&ProductName=G-Pad


Roll Pad:
http://www.giga-byte.com/Products/N...Spec.aspx?ProductID=2526&ProductName=Roll Pad


i thinks this is a generic version:

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=300247535637&ssPageName=ADME:X:AAQ:AU:1123


Ixoft:

http://www.thermaltakeusa.com/Product.aspx?C=1135&ID=1600

can someone explain how works and witch is the best option?
thankss

 

The first two are just making use of aluminum to provide better airflow as well as dissipate heat. Aluminum is one of the best materials for heat conductivity as it transfers heat extremely well, so basically if your laptop has a hot-spot at 80 degrees Celsius the aluminum will heat up in that spot and then transfer the heat to the other parts of the cooler where the air will then carry it away.

The second two products use Sodium Sulfate Decahydrate which has a phase change at 90 degrees Fahrenheit. It basically absorbs any heat beyond that temperature by converting the solid crystals into a liquid.

The first products will always work, but will work better in a cooler environment. The second type of product will ONLY work if you can cool them back into a solid. If you have a computer then runs very cool, or keeps a cool case then the phase change pads will NOT work at all, also if you are somewhere that has a temperature of >=90 degrees anyways you will not be able to experience any cooling. Also don't forget that even if the pad works for you it will only work for a limited time at which point you will need to allow it to cool.

 

I would avoid the two aluminium surfaces as they get very hot. There have been many reviews for both the products that use aluminum surfaces and most have proven the aluminum to actually raise notebook temperatures instead of decrease them

The IXOFT pad I have heard very good things about. I am not very familiar with them but I have seen them in action and reviews say generally good things.

 

thanks for the information
AuroraAlpha: when you said, the pads without aluminium can`t work for long time, how many hours do you think this products work?