PowerColor Radeon HD 4890 Plus 1GB video card review

As well as being able to take in Sapphire's reference clocked Radeon HD 4890 1GB part today, for this launch we were also furnished with one of the first factory overclocked parts in the form of PowerColor's Radeon HD 4890 Plus 1GB.  This board boasts a high clock speed than a reference part, while sticking with the same cooler design and memory clocks as a standard Radeon HD 4890 card - Is this solitary change enough to distinguish it from the crowd?  We're about to put it through its paces to find out.