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First things first: let's go over the big changes introduced with RV670.

While NVIDIA recently transitioned to a 65 nanometer manufacturing process, ATI has gone one step further, and is the first to bring a 55 nanometer card to market. So while keeping many similar architectural features of the R600 / 2900 XT video card, ATI has shrunk and crammed those transistors all the more, and is now able to make a sort-of die-shrunk R600 that is smaller, cooler, and cheaper to produce.  The 80 nm process HD 2900 XT and 55 nm process HD 3850 both have the same amount of stream processors (320), and same number of texturing units and raster operators (16).

One feature that the HD 2900 XT has that the HD 3850 / 3870 do not, is a 512-bit external memory bus, and a 1024-bit internal memory bus. The HD 3850/3870 opts instead for a 256-bit external memory bus, and a 512-bit internal memory bus. While the extra memory bandwidth is nice to have, this reduction significantly decreases the cost of production of the RV670, and, as testing will hopefully show, this does not horribly cripple performance.

The PowerColor Xtreme twist on the HD 3850 reference board design brings a few nicely added bonuses: 512 MB of GDDR3 memory (HD 3850 comes in both 256MB and 512MB flavors), a respectable increase to the clocks (core clock raised to 720 from 668, memory clock raised to 900 from 828), and a non-standard cooler. 

The cooler is responsible for the 'PCS' in the full name of this fine PowerColor product, and stands for 'Professional Cooling System.' The PCS design is made by ZEROtherm, and has an effective looking appearance: basically, the GPU is connected to a slab of conductive metal via thermal tape; from there, heat pipes extend in a ring. The ring is further helped by numerous heat-fins. In the center of a ring is plastic fan, the blows air through the fans and pipes. The cooler is a tad on the louder side of things, but not too bad. While further testing will show how effective this single-slot design is, this cooler does add a bit of width beyond the reference board design of the HD 3850, making a potential CrossFire(X) system possibly a little more challenging to squeeze onto some motherboards. On the positive side of things, this cooler effectively pushes hot air in 360 degrees, which is nice for preventing hot-spots on your hardware.    

Additional cooling for the memory comes from an aluminum heat sink, which appears to be easily removed, via clips that go through the PCB.

The PowerColor HD 3850 Xtreme appears to be a bit longer than it could have been, by a half an inch or so, judging by the spare real estate on the surface of the card. But this card will probably not be hanging off the end of your motherboard, at a length of just barely over 9 inches.  Still, for the price range these cards sure are getting big!

The HD 3850 requires a 6-pin PCIe power connector.

On the back-end of the card, as a change from many of the other video cards on the market today, the HD 3850 features only a Dual Link DVI output which supports HD playback at resolution of 2560x1560 (single link DVI is only capable of transferring a 1920 x 1080 resolution.) The HD 3850 also has a built-in HDMI, offering 5.1 Surround Sound, and a S-Video out.