There's really not any point in having more than 8 GB RAM in a gaming machine, if you're running very many applications at the same time or a several virtual machines, then sure, but for games 8 GB is plenty.
OP: You should add an SSD as a primary disk, it'll be worth it, speeding up load times, both to start OS and software, but also to make dynamic loading of assets in game smoother/faster.
Also, that CPU will not be stellar for gaming, at least not for DCS, that model cannot be overclocked very much due to it's multiplier being locked, DCS is quite CPU dependant, so the faster the CPU the better.
Also, that motherboard does not support overclocking.