Elite Bastards posted a review on the PowerColor Radeon HD 4890 Plus 1GB video card

Compared to a reference board, PowerColor's Radeon HD 4890 Plus features the same 975MHz clock speed for its 1GB of GDDR5 memory, but sees the speed of its RV790 core boosted by 50MHz to a new core clock of 900MHz.

The board also makes use of AMD's dual-slot reference cooler, with the usual additional power requirements of two six-pin PCI Express power connectors.

PowerColor Radeon HD 4890 Plus 1GB video card Review