ojejku

From my observation addons that have noticeable and a big (not even saying huge) impact on performance are addons for AI like ZeusAI, SLX or some modules from GL4. It's obvious since more AI calculations in the background is killing a good performance in Arma2. Try disabling/enabling them in order to compare the performance. For example in the vanilla scenario "Attack on a village" I got at least 10 fps drop using ZeusAI. @Günter Severloh I see not a single point in keeping addons of the same type in the same folder. I suggest to keep addons in a separate folders and use arma 2 launcher which provides profiles features, where for each profile you can choose which mods you would like to run.

Disabling vsync is pointless unless it's coded wrong. I have vsync on and forced triple buffer for direct3d in radeonpro app. Triple buffer works and it's really nice to have vsync on. @Marc15yo I suggest installing 11.1a hotfix driver, it is a really stable on my 5870 whereas on 10.12 I had BSODs (not only I, just have a look on amd official forum) etc. Moreover the gameplay seems to be smoother. @DMarkwick There is sth in what you are saying, but on the other hand the fps drop from 60 to 20-25 is very noticeable so even without the FPS counter you can get angry & frustrated.

@Marc15yo ArmA2 engine relays on and utilizes much more CPU than GPU, so upgrading your Phenom to for instance Core i5 could give you a nice boost. I have i5 also, but don't expect miracles, you will still get fps drops to 20-25fps, especially in campaign, even in OA. If we could have a hypothetical view on Crysis 2 engine (Crysis 1 also) then we can see how the engine should be designed&coded. Yeah, it's probably the greatest engine in the game industry the world has ever seen. It's capable of rendering huge terrain with a lot of not scripted AI, really great physic, covering land/water/air units/environment and in the same time providing such unbelievable visuals and motions, scalable and undeniably well optimized. It just uses the all resources you got at the maximum level. Just have a look on this video (let's say it's in the ArmA universe) http://www.youtube.com/watch?v=d-7ME7rkAkQ&feature=player_embedded and think about how great it could be to see ArmA in such engine...

@Marc15yo Totaly agree with you. I'm fed up with opinions like "Don't compare it to other games, Arma2 has billions of billions of billions objects to render whereas AI is not scripted (real time calculations), 100km^2 of terrain etc etc.". Why do people try to change the reality ? lying to yourself ? How the hell they know how the engine works ? I just can't believe that people are so afraid of the truth ? The truth is that the engine is not well designed&coded, well let's say it definitely could be better. BTW I love Arma2 as we all do here, in this community but BiS definitely needs a good competitor on the market and then we could see a whole different story... Try to disable (at all) postprocess effects, it kills my 5870 too.