Elite Bastards posted a review on the PowerColor Radeon X1950 PRO SCS3 (Silence Edition) video card

We spoke in our introduction of the pitfalls of creating a passively cooled high-end board, and the largest of those pitfalls is, of course, heat output. Which brings us to the monster of a heatsink we have before us - This thing is huge! The solution employed by PowerColor is generally based around Arctic Cooling's Accelero S2 cooler, and uses quad heat pipes to pull heat from the GPU away from the core, where it is dissipated by the large surface area and fins of the heat sink via cold air moving through the case (thus assuming reasonable ventilation in your chassis of course). The memory on the board also finds itself equipped with heat sinks to pull heat away from the RAM, where once again it is moved away by those thirty-one fins.

PowerColor Radeon X1950 PRO SCS3 (Silence Edition) Video Card Review