Priced at $99 and $79 respectively, the Radeon HD 6670 and HD 6570 are positioned at very attractive price points, and are intended to succeed the current HD 5670 and HD 5570 graphics cards. The Turks GPU found in the Radeon HD 6670 is clocked at 800MHz while in the HD 6570 it will be running at a more modest 650MHz, with both offering 480 stream processing cores, 24 texture units, 8 ROPs, and a 128-bit memory bus.
In terms of performance both the Radeon HD 6670 and Radeon HD 6570 are up around 10-15% over the Radeon HD 5670 and Radeon HD 5570 they are replacing. They also offer better overall performance than the Nvidia GeForce GTS 240 / 440 they are going up against, but with stocks of previous-generation cards still plentiful and many manufacturers running promos, you'll be able to find much better performing cards for the same or even less money -- like the Radeon HD 5770 and GeForce GTS 450, which are both regularly on sale for under $100.
At least until their launch prices inevitably go down, the real value of these cards is found not in the performance but in their low-power requirements and ability to support multi-monitor configurations. The 6570 has a TDP of 44 watts and uses only 10 watts when idle, while the 6670's TDP is 66 watts and consumes 12 watts while idling. Both cards feature a low profile design and neither of them requires an external power source.