In the first months after the product release AMD has limited all HD 4870 cards to use the AMD reference design. Add in board partners could not change any component of the card and clocks had to be the same ones as the reference design.

Palit is one of the first AIBs to release a custom HD 4870 version: the Palit HD 4870 Sonic Dual Edition. It uses a completely revamped cooling system that uses two fans to keep the card cool. Also included is a DisplayPort connector and a “Turbo” switch. The Turbo switch lets you select between two different operating frequencies. In normal mode the card will run at 750 MHz core and 900 MHz memory clock. In Turbo mode an additional overclock is enabled with 775 MHz / 1000 MHz.
Even though the changes are numerous Palit has managed to keep the retail price below $299.

• http://www.techpowerup.com/reviews/Palit/HD_4870_Sonic_Dual_Edition