I upgraded from a GeForce GTX 770 (2gig) to an MSI GeForce 1070 (8gig). It's selling for $400 on Amazon, which is a big difference between the 1080. Installation is incredibly easy; the last time I manually installed an upgraded video card was probably 15 years ago, when manual BIOS updates were required. I installed the hardware and GeForce Experienced recognized new hardware and installed new drivers.
Noticed a pretty big improvement in SB, while ArmA performance has not changed at all. Kudos to the developers, as I know they are currently (and always) looking at ways to improve the performance of the game.