We were positively surprised by AMD's new Radeon HD 7800 Series in our launch day review. Since then nothing has changed. The ASUS HD 7870 Direct CU II uses the same reference design PCB, adds a bigger cooler and increases clock speeds significantly.
Going from 1000 / 1200 MHz on the reference design to 1100 / 1250 MHz on the DC II resulted in a real life performance improvement of about 5%. While I would have expected a bit more, given a 10% increase of GPU clock, it is still a noteworthy improvement and comes free, since ASUS sells their card at the same price as the reference board.
Despite the overclock out of the box we saw significant additional manual OC potential, up to 1260 MHz, which is a new clock speed record here at TPU. No other card has seen higher GPU clocks in a VGA card review. We have almost gotten used to see memory clocks above 1500 MHz, the ASUS HD 7870 DC II is no exception here with 1620 MHz.
Power consumption during typical gaming is slightly increased, due to the higher clocks. Furmark shows a large increase of almost 100 W over the reference design though. I have to admit, Furmark is not a realistic test for every day usage, but it can still provide an additional data point, for worst-case scenarios for example. Such a large increase in power consumption is very uncommon, especially considering that the DC II uses the same power circuitry as the reference board, voltages are the same too, only clocks are higher. While I can't provide a conclusive explanation for the power increase, it seems most likely to me that the higher clock speeds cause the increase in Furmark power.
Another thing I didn't like was the excess noise coming from the card under load. With 45 dbA it is clearly "noisy". Cards like the recently released GTX 680 are quieter and faster, even the AMD HD 7870 reference design is, and we know that those are usually noisy, so that board partners can market their "low-noise" custom boards. Personally I am using a GTX 580 Direct CU II in my system because it is quiet, so I kinda got used to "ASUS Direct CU" = "quiet". Unfortunately not with the HD 7870 DC II.
In terms of pricing I have to applaud ASUS for releasing their card at the same pricing as the AMD reference design: $360. However, $360 is still a hefty price for a card like the HD 7870, other options on the market offer better price/performance right now.