ARMA 3 is a pretty intense game, with dozens of units in the AO, sometimes frames can drop to slideshow level, I'm sure you've all tryed the usual; dropping graphics quality, reducing view distance and worshipping the dark spirits to increase you FPS. I'm going to try and show you a couple of things you can do to increase your FPS without neccesarily sacrificing visual fidelity. This isn't going to make the game run at 4k ultra hd silky smooth 140 FPS, but for those of you with ageing PC's such as myself, those extra frames are what you need.

*Step 1 - Profiling Build*
An easy way to score a couple of extra frames is to use the arma 3 profiling build, this is a constantly updated branch of the game, that is compatible with the release build. (I've been using the profiling build for years now with zero negative effects on gameplay, the only time i've ever had problems was when APEX came out and the profiling build hadn't been updated, but those situations are few and far apart.) With the profiling build new performance binaries are added almost daily, getting us ever closer to the dream of silky smooth gameplay.

In order to access the profiling build, right click on ARMA 3 in your Steam Library and click properties, navigate over to the "betas" tab and enter the code "CautionSpecialProfilingAndTestingBranchArma3" without quotes. Then select the performance profiling build from the dropdown and let the game update.
https://my.mixtape.moe/hupvdu.png

If all goes according to plan, you should be running the cutting edge space age profiling build, this will boost performance between base game updates.

*Step 2 - Memory Allocators*
Another easy way to boost FPS is to use a different memory allocator. A memory allocator is a .dll file that (AFAIK) dictates how the game uses memory, allowing for smoother gameplay without stutter or lag. Up until a while ago the game used the default Windows memory allocator, and it was p bad. But recently they've switched to the Intel TBB 4 Allocator, which is an improvement but personaly I feel its kind of dwarfed by the xtbb memory allocator, a custom malloc made by the community.

xtbb can be downloaded from ARMAholic here: http://www.armaholic.com/page.php?id=31217

Follow the instructions in the included download to correctly configure the malloc for your PC, once thats done, in your ARMA 3 launcher, go to parameters, and then Advanced, and change your Memory allocator (64-bit) to cma_x64 or whatever dll you just installed. Launch the game to make sure everythings hunky-dory before continuing.
(Disclaimer: if you set this up incorrectly, i have no responsibility for what it may to do your game or CPU, DLLs are scary, be careful)

*Step 3 - Other launcher settings*
ARMA 3's launcher is a powerful thing, and if you've played with us before, you know just how important it is for mods and settings, but there are a couple of options that are buried in parameters that can make getting into the game, and playing the game, smoother and easier.

I will go down the list of settings that I have changed that have helped this, there aren't many, don't worry.

-Platform: Set this to 64-bit if your PC is 64-bit, and 32-bit if your PC is 32-bit, fairly self explanatory
-Show static background in menu: This options means you won't get the pretty background when you hit the main menu, but the game will load faster as it won't have to load Altis or whatver before you've even started playing.
-Skip logos at startup: this option will mean you get into the menu even faster.
-Enable Hyper-Threading: A magical option which I don't quite know how it works, but I've gotten better FPS using this option so whatever.
-Memory allocator (64-bit): As mentioned earlier, this should be set to either Intel TBB 4 or cma_X64
-NoLogs: This option should be on if you aren't that one person whose game crashes every 15 minutes, FPS increase is negligible however, so do what you want.
-World: This option dictates what map is loaded for the main menu background, and should really be set to Empty, this isn't an arcade game so you don't really need a demo screen.

You are welcome to adjust any other settings and see how that goes, but do so AT YOUR OWN RISK

*Step 4 - Ingame Video Settings*
This is where things get a little trickier, not everyones PCs are the same, so ingame settings will vary based on PC strength. If you can run the game at max everything with no frame drop, then this guide isn't really for you. But for the rest of us theres a couple of general rules to go by when adjusting in game settings:

-If the game is just uplayably laggy, it might be worth dropping the sampling rate, that means that the game will render everything except the UI at a lower resoultion, then increase the size to match your resolution. It won't look pretty and will be gnarly blury, but if its the difference between playing the game and not, its worth it. Play around with the sampling setting to try and get it as high as you're comfortable with.

-Clouds and PIP (Picture in picture; the mirrors in cars and screens in game): These are notorious frame rate killers. If you're FPS is pretty bad while in vehicles, it probably best to turn off PIP, it may not look pretty, but hey its showbiz.

-ANTI-ALIASING: This is the big one, most wanted number one for FPS murdering, FSAA (Full Screen Anti-Aliasing) may look pretty, but for some of us its an absolute tanker of FPSes, try and avoid using this if you're getting upsetting low fps, use PPAA (Post-Process AA) if the game is jaggier than Vasquez Rocks and you need your AA fix. Plus SMAA has this cool sharpening effect that IMO looks pretty good.

-Shadows and Water reflections: again these are very much dependant on your PC, but bumping down reflection quality isn't really noticeable and will save a few frames.

-VIEW DISTANCE: Okay this is it, the big bad, how far your little soldier eyes can see. View distance is a tough subject in A3, set it too low and while you may get a decent FPS, you're a disadvantage to that lone sniper miles away, or that tank that is nestled just out of view.
View distance is broken down into 3 sections in ARMA: Overall, Object and Shadows. Shadow draw distance is an easy fix set it to whatever you're comfortable with and you won't really have to worry about it again. Object and Overall view distance are a little trickier. Overall viewdistance is how much of the terrain you can see. Once again depending on your PC, this can be set to about 1500 or 2000 metres without issue, but can be adjusted in game with MCC's handy view distance feature on your scroll wheel, making changing it on the fly easy as. Object view distance is where the frames are really at, for certain object heavy maps, not naming names (coughTANOAcough) object view distance can be the difference between a slide show of different combat pictures, and true visceral combat. This will need fine tuning and adjusting until you can find a balance that doesn't upset your PC or your eyes.

There a couple of extra bits than can help with view distance related FPS woes however. ACE 3 has a built in view distance limiter that adjusts the view distance based on what vehicle you are in, it can be found by starting up the virtual arsenal, pressing escape and clicking ACE 3 in the top left hand corner of your screen, from there, click view distance limiter in the dropdown menu and adjust as you wish, setting your Dynamic Object View distance to high works well, FoV based is a bit sketchy so watch out.
MCC also offers the in game performance controls mentioned earlier, and finally, there are two mods that I use that vastly improve situations where you "Didn't see that tank in the distance" Or "Could only hear the helicopter flying over" These are MRB Vehicle Visibility and MRB Air Visibility, these two mods are on the workshop and basically draw ground and air vehicles regardless of your object distance, meaning you can spot helicopters before they strafe your entire team. These do affect performance however, especially the ground vehicles addon, but not by much, so you can use them worry free.
Air Visibility: http://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=929396506
Ground Visibility: http://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=930903722

*Step 5 - Shoot men in ARMA 3*

Okay you've made it this far, congratulations, you are now free to shoot a variety of soldiers as a variety of other soldiers, If you don't regularly play ARMA with FPAir, follow the pinned posts to get the mods installed and for ♥♥♥♥♥ sake

**UPDATE YOUR MODS BEFORE YOU PLAY**