I had a 6600XT before this and i just wasn't happy with performance of the card. I had memory crashes constantly. I was worried that Arma 3 may not run properly because it is an older game. But my worries were unfounded.
The moment I started it up and hopped in game, the performance was buttery smooth. ZERO skipping and tearing. and with all the graphics cranked to the max I still got pretty good performance. if I wanted smooth framerate however i did have to crank the ani aliasing down from 16 to 8. But other than that, everything was set to ultra nightmare performance. And it ate it up.
The card I bought was the ASRock Phantom Gaming Arc A770 16GB. I got it for 399 CDN. (294.86 US Dollar) And its a solid over built card. Even when playing Cyberpunk 2077 the card rarely went above 60 degrees.
So from me it's a solid recommendation.