I'm planning on moving the arma server to another host anyway soontm , so that is not the issue here that much, the servers runs okayish now, unless we get 8 or more people on it.
But anyway, the main question is whether or not the upgrade would be worth it when only taking into consideration gaming at 2560x1440p. @fasauceome & @Tom H already gave me some good insight on this, thank you for that!