The back-plate works as a heatspreader over components on the reverse-side of the PCB, especially drawing heat from the area behind the GPU, it is highly perforated and attracts convectional air-flow. Aside from cooling, the back-plate adds to the card's aesthetics. With SC clock speeds of 625/1250/850 (3402) MHz (core/shader/memory), the EVGA GTX 470 SC+ is priced at $375 on the company's online store.
Source: TPU