You will not get a Dev saying that everyone must set the FPS in the command chat,they may offer you tips if YOUR system is having a problem but as much as I feel sorry for you guys this is NOT a game problem.
If it was a game issue then everyone would have it.
I do not have a 5k rig or anything near to it.
My specs are a dual core 2.66,4gb RAM,Vista 32 and GTX275 card.
Now I have read a lot better system's than mine having this problem and having read alot of them I have to say you best look at your system and maybe the cooling or indeed the power.
Like I said if this was a game problem not only would everyone have it but you can be damn sure Cryptic would have it sorted.