"I know aluminum gives heat off faster than Copper, but I thought copper absorbed heat faster than aluminum."
You are correct. The reason the aluminum one is a better choice when cooling a graphics card GPU is more becuase of the small size. Let me clarify. Copper will absorb heat faster,
but it needs more airflow over the surface to counteract the bad "shedding" qualities of a copper HSF and remove the heat. When using a copper HSF on say a CPU, much higher CFM fans can be used like the Delta or even larger 80mm fans to more effectively remove the heat from the HS. In a application like a graphics card, the highest CFM you can really have right on the GPU (not considering a card cooler) is maybe ~10-15CFM, or with the fastest 50mm fan they make, 20CFM. This is just not enough airflow to effectively cool those copper HSF's. Also, the design of the copper heatsinks is not the best, and you can tell they are cheaply made. The Alpha with it's pin style design has much more surface area, and it's even larger than those copper ones. If you ever get a chance to look at the fin design on one of the copper coolers, you will see what I mean..
