NVIDIA's new GeForce GTX 780 has established itself as the new high-end graphics card of choice for serious gaming at 2560x1600. Built on the same GK110 graphics processor as the GeForce GTX Titan, it represents the best GPU technology NVIDIA has to offer at this time. Compared to the GTX Titan, the differences are relatively slim. NVIDIA disabled another streaming multiprocessor (SMX), reducing the CUDA core count from 2688 to 2304. Also, the GTX 780 comes with 3 GB of GDDR5 memory instead of the 6 GB the GTX Titan has, but that's pretty much where the differences end.
When looking at the performance of the ASUS GTX 780 DirectCU II OC, we see performance that matches the GeForce GTX Titan. Compared to the GTX 780 reference design, the improvement is 7%. AMD's fastest single-GPU card, the HD 7970 GHz, is 22% slower—no danger at all. While AMD wants to put the HD 7990 on the performance throne, our own review shows that it is just not competitive enough, and also too expensive with $1049.
ASUS has equipped the GTX 780 DC II OC with their latest DirectCU cooler, which brings significant improvements in thermal performance over the previous design. It combines new fat heatpipes that can carry more heat with a new dual-fan design that optimizes airflow. As a result, the card runs at a cool 67°C during gaming, which is much better than any other GTX 780 we tested so far. This also optimizes performance because the GTX 780 will throttle itself some more at 80°C. However, this focus on temperatures causes noise levels roughly equivalent to the GTX 780 reference design, which is certainly nice, but I had hoped for much better. The cooler could easily provide great noise levels if ASUS would have chosen better fan settings in their BIOS. Such low temperatures really don't provide anything for the user, but lower noise could set the card apart from the competition. What I really like is that ASUS includes a backplate with their card, which greatly improves the look and feel of the product while also provides protection against accidental damage.
Gaming power consumption is slightly lower than the reference design, even with the overclock out of the box, probably because of the upgraded 10-phase power design. The differences in power consumption are kind of small, though, and will not affect everyday usage.
Overclocking on our sample worked very well, reaching the highest clocks of all GTX 780 cards we tested so far. The overclock is also very high in percentage because the card runs rather low clocks out of the box compared to other custom GTX 780 designs. We gained almost 20% real-life performance as a result.
While final pricing is not in yet, ASUS mentioned that they are looking at a $699, maybe $689, price point. The reference design at $649 is not cheap in the first place, and adding $50 seems a bit much, especially since the card does not stand out when compared to other custom GTX 780 cards with a lower pricing. After testing four GTX 780 designs, I have to say that all custom designs are so far similar enough; it really makes no difference which one you buy. If the GTX 780 is too expensive for you, the GTX 770 comes at quite competitive pricing, and it still packs enough punch to handle all titles at full HD.

Update: ASUS sent me an updated BIOS that improves gaming noise levels of the card dramatically. NVIDIA's Boost 2.0 tries to manually adjust fan speed levels to avoid sudden changes. ASUS did not take this mechanism into account, so the card ended up running higher fan speeds than intended. With the new BIOS, the card reaches 72°C under load (good), and noise levels are reduced by 6 dBA (very good). You can find the updated BIOS here, but it will also be included on all retail cards.