Upgrading the CPU, worth a thought? Have: Core i7 2600k 3.4 GHz Sandybridge

[forteh 11]

What if slower clocked RAM is mixed with 2133 MHz RAM?

I have "EKL Alpenföhn Matterhorn" fan, I hope that's enough cooling... will see.

I don't think that's going to work, I believe all of the ram will run at the slowest speed of the installed sticks. If you can't stretch to 16gb 2133mhz get 8gb and possibly another 8 at a later date.

I have never seen more than 5-6gb ram usage whilst playing arma3 so eight will generally suffice. I only upgraded to 16gb because I use solidworks on my machine and 8gb is nowhere near enough!

[galzohar 31]

If you stick to missions that don't stress your CPU you'll have great FPS. Especially if you don't push your graphic settings (max settings with GTX 970, at the most graphically intensive spot I could find near Kavala, I get 37 FPS in single player, no CPU bottlenecking since FPS is 60 while looking at the sky).

Doubling the power of your current CPU is probably not going to happen at least until a new generation comes out. 2500k at 3.4GHz is a fine CPU to have for gaming.

Keep in mind that the crazy missions that give you 15-20 FPS will still only give you 30-40 FPS at the most if you double your CPU power. With a more realistic CPU - A lot less.

Again, I would try find nicer missions (like DTAS) before jumping in on an upgrade.