Radeon HD 7870 (GV-R7870C-2GD) feature Ultra Durable VGA+ PCB and custom cooling. Card has three fans included in one system called WindForce 3X, which is made for high-end cards released by GigaByte. Gigabyte is preparing this card with an overclocked clocks by 5-10%.
Radeon HD 7850 (GV-R7850C-2GD) is smaller than 7870 and feature only two fans with WindForce cooling solution. Card is prepared with overclocked clocks by 5%.