difference of 10€ between Asus Direct CU II OC R280X and GTX770! (...) what are your opinions about these 2 cards?
The big things you mentioned:GPU performance
- Close enough to call "the same", because of...Drivers
- AMD's driver team has made remarkable progress in the last year or so, but I can tell you from experience with both that Radeon cards still have problems with apps outside the mainstream, particularly Unity-based games, which use OpenGL. In other words, AMD's OpenGL driver is still pretty broken. However, if you mainly play DirectX games, this is mostly irrelevant.VRAM
- You're right on the money here. I regularly exceed 2GB of RAM usage in Warframe, a 64-bit DX11 game. It doesn't even have especially high-quality assets; I think it's just caching stuff in my expanse of video RAM. Still, after the initial load I have literally no load time, so that might have something to do with it; as I opined-and-had-confirmed in a recent thread here on the forums, assets are what takes up the RAM, not the framebuffer, and assets are only going to climb in quality as developers stretch their legs into that 8GB RAM pool on the consoles.Power Consumption
-It's a wash.Overclocking
- Your 560Ti card was the revised midrange Fermi, GF114. GF114 and GF104 were known for their overclockability, so you kinda picked a bad example; most cards don't quite do that well without significant voltage increases. However, I will tell you that my brother runs a pair of 7970 cards (non-Ghz!) at nearly 1200Mhz. A pair of them, note. So, obviously it can be done. ( ･ω･)ﾉGame bundle
- I don't even want the games in Nvidia's bundle. Do you? (Although I guess you could resell them.)
Basically what it comes down to are whether you intend to mostly play older games and indie games, or newer games and AAA games. The GTX is better for the former (due to better drivers and 2GB VRAM), and the Radeon is better for the latter (due to worse drivers and 3GB VRAM.)
Anything else to consider?
Look at the coolers on the cards and decide which one's design you like better -- not as much aesthetically, but, well -- me, personally, I prefer a 'blower' or centrifugal design, whereas some people prefer regular (axial) fans. Blowers vent the hot air out the back of your case, but usually don't cool as well and are noisier. Axial fans will cool better, but they dump all that heat from your GPU -- and it's a lot -- into your case, to heat up other sensitive components, like your mainboard and (especially) your power supply.