Some stuff runs poor on my OCed FX8120 (4.2GHz), In Arma 2 wasteland I get 30ish frames and my friend with a 2500k stock clock and get 45-40 and I have far better GPU.
in my opnion the the engine for arma is poorly codded as well as the game but if anything that reinforces your reasons for a better cpu to compensate for that crap, if you cant wait till then key most important things to note about x79/1155 in my opinion once again. only go for x79 if you want a hex-core sollution as 1155 offers better performance per watt as they are lower wattage cpu's and intel wont be making a hex-core 1155 socket cpu. also 1155 supports faster ram and has better usb 3.0 support than x79, some 1155 boards have thunderbolt aswell. 1155 does'nt oc aswell as x79 but not by much and 1155 runs a little warmer.
If you think you can wait a little while longer till Q2 there are some things you can do to push better frames. turn off 3d stereoscopic make sure your gpu is running physx not your cpu, also turn off or down the following in game shadows/post-fx/anti-aliasing/anti-stropic filtering and in some games particles. you may also want to cosider advanced system care software from iobit for the turbo boost function (it frees up ram and and cpu runtime by closing and opening background programs) it can also turn off/on windows theme's like aero etc without having to use the control panel it's good user-friendly and convinient software (i even use the the payed for version after years of using the free one which is still good) also the system maitnence functions are good just turn off the reg edit and reg defrag functions (never let third party software touch your registry ever lol) oh and the disk defrag too just cause of time more than anything. also i believe your cpu can support faster ram, and ram with tight quick cas timmings is good like 7-7-7-24 (lower numbers = faster) hope this helps anyway, let me know what you think