Yes the scenery in that video looks very good.
However you have to consider the difference in complexity when you compare with FS (9 or X).
The differences are huge, and covering several domains: scenery, physics, AI, systems, weather etc...
Scenery: it looks good but nothing can be seen at more than 2-3 miles away. We get some fog with imprecise and blurry terrain after that threshold. Making an approach at 5 to 10.000 feet like we do in FS would simply be impossible, since the airport would not be visible until very very close.
Also, the terrain itself is not a dynamic terrain. It's fix, build by hand, which means it has been optimized everywhere it could. This non-dynamic style makes it much easier for the programmers to optimise the display of such things, leading to performance boost. Unfortunately, this system won't allow you to add your own sceneries/landclass/improvements so easilly. It won't allow you to model a very large area either.
Physics: the physics of the various vehicules in Arma is closer to "XWing vs Tie Fighter" than FS. There are very few parameter being taken into consideration. Basically, if the plane goes fast enough it can fly, else it kind of stalls. This extreme simplicity lead to simple flight model computations, which lead to much fewer work for the CPU, which leads to better performance. Sure there is some damage handling but it's very basic, you won't get any precise damage like in IL-2 for example, and of course you won't get any kind of "precise" effect for a given damage. Simplicity again, leading to better performance because the CPU has very few things to do.
AI: the game has some AI, but when you speak about 100 players it's not AI anymore, it's just real players. Having 100 AI would not lead to the same impact for example, but yes I know that Arma does a pretty good job in this area, I've seen those fantastic videos with the huge simulated AI conflicts.
However, there is no ATC system, and in FS once you install some AI packages you have virtually more than hundreds of AI planes flying on the whole planet.
Systems: there are more than basic in Arma. You won't be able to start your plane, nor to interact directly with the various instruments in your cockpit. No lights, no radios with several frequencies, no VORs, no ILS, no anti-ice, no mixture, no RPM control, no generators, APU or battery, no damage due to incorrect engine handling, no effects of flying environment (pressure, altitude, temperatures etc...) on the engine behavior. FS has all of this, but Arma does not. Again, that means much less computations to do for the CPU, leading to better performance.
Weather: in Arma you won't get a dynamic weather with appropriate effects on atmospheric pressure and temperatures. You won't get thermals, changing winds according to altitude, layers of visibility etc... You won't get any impact on the behavior of the plane/engines because of those parameters. You won't get anything like carburetor or propeller icing, and if it starts to snow, the surrounding lands will not get white. Also, I don't know if you can choose a season in Arma ? If yes, does it impact the look of the terrain (color of trees etc...) ? That's also some heavy stuff removed from the CPU you see.
Of course, in Arma the CPU definitely HAS hard stuff to compute, for the elements that you mentionned previously for example (bullets etc...), but the challenge is different. Basically, you are severely underestimating the complexity of the FS world.
Edited by Daube, 12 November 2010 - 05:44 AM.