Elite Bastards posted a review on the PowerColor Radeon HD 2900 XT 512MB video card
A quote from the article:
PowerColor Radeon HD 2900 XT 512MB Review
PowerColor's Radeon HD 2900 XT board is based entirely on the reference specification from clock speeds to cooler - As we just covered, that means a core clock of 740MHz, with GDDR3 memory clocked at 825MHz.
PowerColor's offering features that flame-imbued, dual-slot cooler, which sits atop the large heatsink with two heat pipes that cover the R600 GPU core. CrossFire is supported via two inter-GPU connectors (which are hidden behind the cooler in this shot), and the required power to run the board comes via a combination of a six-pin and eight-pin PCI Express connectors (although two six-pin connectors can also be used, with the eight-pin link only required to enable ATI's OverDrive overclocking functionality).
PowerColor Radeon HD 2900 XT 512MB Review