Elite Bastards examine the first non-reference Radeon HD 4850 board in the form of Sapphire's Radeon HD 4850 TOXIC. A quote from the article:

Compared to the reference core clock speed of 625MHz, Sapphire's Radeon HD 4850 TOXIC boasts a 50MHz factory overclock, leaving us with a final core clock speed of 675MHz for this board. Memory clocks see a more impressive increase in speed however, with a factory clock of 1100MHz used here, some way above the 993MHz reference memory clock.

Of course, aside from those clock speed bumps, the real news here is the use of a third-party cooler, and taking a look at the board itself we get our first glimpse of it. The solution on show will doubtless be instantly recognisable to many of you as a part provided by Zalman - We've seen their offerings put to good use on other graphics boards in the past, so it certainly seems like a pretty good choice. While the cooler itself doesn't cover the board's memory modules, heatsinks are attached to cool the RAM to some degree as well.

>> Sapphire Radeon HD 4850 TOXIC 512MB video card review