Just a small concern, but the fins on the heatsink are supposed to enhance the cooling by convection of the air around them. As they appear to be placed inside the case, they do not seam to have a lot of space for air to circulate around them.
Not necessarily, it depends on the amount of heat produced and whether you have a fan or not.
The fan would be used to blow air through the fins and basically blow the heat away - in this case, you'd need to have an area where air can be sucked in and blown out.
Without a fan, the air wouldn't move around a lot - not even if there's an opening. The cooling is (of course) a lot less than when using a fan.
The fins are simply there to increase the overall area where heat is in contact with air.
The air WILL still cool it, even inside the plastic case.
And as long as the air is cooler than the CPU, then it will work
Taking this into account wouldn't it be better (cooling and price wise) to just have a copper cube to act as a thermal capacitor and rely on the usb port to dissipate the heat through convection (as it actually has contact with the air outside the case)?
It needs to be tested to be sure but my intuition tells me that these new aluminum heat sinks will not be as effective as the copper ones, as 1st they look less dense (more space between the fins), and 2nd they are aluminum so they have a lot less heat capacity per unit of volume.
The USB port doesn't have any fins, so the area where it's in cotact with air is VERY little.
Also, as the USB port only has a thin metal layer (compared to the thick heatsink), it would heat up a lot faster.
Combine a faster heating with less contact to air to cool off and you can understand why this would probably make things worse.