Elite Bastards posted a review on the Sapphire Radeon HD 4670 GDDR4 512MB video card

As our introduction blurb made clear, the two major changes to this particular board are the use of a custom cooling solution, while from a performance perspective the removal of GDDR3 memory to be replaced with 512MB of GDDR4 also sees a 100MHz clock speed increasing, giving this board RAM modules clocked at 1100MHz against the 1000MHz parts on a reference board.

Sapphire Radeon HD 4670 GDDR4 512MB Video Card Review