Then how do you know it can run ARMA 3?
A very good place to find that kind of information would be the game developer's website:
https://arma3.com/requirements
MINIMUM
OS Windows Vista SP2
Windows 7 SP1
(Mac and Linux experimental versions available. More info
here)
PROCESSOR Intel Dual-Core 2.4 GHz
AMD Dual-Core Athlon 2.5 GHz
GRAPHICS NVIDIA GeForce 8800GT
ATI Radeon HD 3830
Intel HD Graphics 4000 Graphics
Nvidia GeForce GTX 560/AMD Radeon HD 7750
GPU MEMORY 512 MB
DirectX® 10
RAM 2 GB
HARD DRIVE 15 GB free space
AUDIO DirectX® compatible on-board
OTHER Internet connection and free Steam account to activate
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RECOMMENDED
OS Windows 7/8/10 64-bit
(Mac and Linux experimental versions available.
More info
here)
PROCESSOR Intel Core i5-2300
AMD Phenom II X4 940 1GB
GRAPHICS Nvidia GeForce GTX 560
AMD Radeon HD 7750
GPU MEMORY 1 GB
DirectX® 11
RAM 4 GB
HARD DRIVE 25 GB free space
AUDIO DirectX® compatible soundcard
OTHER Internet connection and free Steam account to activate