Elite Bastards posted a review on the Arctic Cooling Accelero S1/S2 Turbo Module

When we looked at Arctic Cooling's Accelero S2 GPU cooler a month ago, we couldn't help but be impressed. It certainly looked the part, courtesy of its hefty construction, but more importantly it delivered on the performance front too - The Radeon X1650 XT board we used as the guinea pig for our testing enjoyed not only higher overclocks than those seen using the reference cooler, but the GPU also ran substantially cooler as well. All of this, and with a completely silent cooling solution.

However the Accelero S1 and S2's potential doesn't end there, thanks to the recent release of a 'Turbo Module' for these coolers. The basic principle of the Turbo Module is to turn these coolers back from passive to active parts, courtesy of two small yet quiet cooling fans which snap on to the cooler to provide additional cooling (and thus drops in temperature) without adding to the overall noise of the system excessively.

Arctic Cooling Accelero S1/S2 Turbo Module review