As we have already mentioned, the new Radeon HD 4670 is powered by a GPU that shares the same base architecture at the Radeon HD 4800 series, that has been scaled down for the mainstream market segment. To see just what has been changed, we've got a breakdown of the Radeon HD 4600 series' features listed side-by-side with the previous-generation Radeon HD 3600.
As you can see, the Radeon HD 4600 series has been improved in every meaningful way over the previous generation. The transistor count increased from 378M to 514M, which resulted in a 20% increase in die size, but AMD was able to use those transistors very effectively and have increased the 4600 series' anti-aliasing, Z/Stencil, and Texturing capabilities four-fold. The number of stream processors in the GPU has increased from 120 to 320 (down from 800 in the RV770), and memory bandwidth has been increased to about 32GB/s, a bump of approximately 25%. Those of you with good memories will realize that this new mainstream card has the same number of stream processors as last year's RV670--which was used on the Radeon HD 3870 and 3850.
Although its specifications reveal a much more powerful product than ATI's previous generation mainstream graphics card, the new Radeon HD 4670 is still an unassuming, single-slot card, with a relatively short PCB. The card you see pictured here is equipped with 512MB of 1GHz GDDR3 memory with a 750MHz GPU clock. Please note, however, that ATI has also informed us that 1GB versions of the HD 4670 are also slated to arrive, that use standard DDR3 memory to keep costs in-line.
The single-slot cooler used in the card consists of a slim-line copper heatsink with a dynamically throttled fan, that proved to be nice and quiet during testing. ATI was able to equip the card with a relatively quiet and small cooler because the Radeon HD 4670 has a max board power of only 59W, which is within PEG (PCI Express Graphics) specifications. Since the card doesn't require exorbitant amounts of power, a supplemental PCI Express power connector is not necessary.
The outputs on the Radeon HD 4670 resemble just about every other modern graphics card and include dual, dual-link DVI outputs and an S-Video / HD component output. HDMI out with audio is also supported through the use of a dongle--just like the Radeon HD 3800 and 4800 series cards.