From the Better Review
With a larger surface area, heat can be dissipated more efficiently. If we had a fan blowing onto the heat spreaders I'm sure we would get much lower temperatures. Unfortunately, we don't. In their current state, these RAM heat spreaders don't do a whole lot for cooling. The RAM in testing remained stable both with and without the heat spreaders. The only difference that I noticed from the copper to the aluminum was the added weight. The copper had to weigh at least twice as much as the aluminum spreaders. Both versions provided the same temperature results. I do like the process in which these spreaders are held together. The locking mechanism gives a solid feel, and the chrome locking clip ensures things will not be moving around while putting your RAM back in their slots. If you are one who is looking to add a nice touch to your modded case, these heat spreaders do manage to give your RAM sticks a whole new look.