OCC has published a new review on the Powercolor HD4670 PCS

While trying to overclock the HD4670 I was pretty much stifled at each turn. Even moving up 20MHz would cause a driver crash and require a reboot. Trying to scale the memory upwards was almost as bad. The initial driver was the source of some of the issue. Upgrading to the 8.10 Catalyst suite allowed the card to post a 10MHz gain on the core and and 35MHz on the GDDR3 memory. Temperature was not an issue at all during the overclocking of the card. Those in fact, stayed a respectable 59 degrees Celsius maximum. Since this card gets all of its power through the PCIe slot, it's not a barn burner by any means. On a percentage basis, this represent gains on the core of less than 2% and 3.5% on the memory. Numbers that would truly not show an increase under the benchmarking suite, so this card was not run overclocked.

Powercolor HD4670 PCS Review