I would not recommend you to invest any money in new single cpu rig, right now only dual cpu rig is worth. If you already have X99 rig and want to boost, then its different matter. If getting good deal on used rampage V, then buy it. E5 2680v3 will boost to 3.3Ghz all core but only on low loads, on heavy load it will drop to 3.1ghz, with E5 2690v3 speed will drop to 3.2-3.3Ghz. You can get 5% more by bclk 105 but it may not be stable. These both are not worth this mod. Only cpus i would recommend you are E5 2686v3, E5 2699v3, E5 2696v3, E5 2698v3. E5 2696v3 is best among all, it can reach 4ghz.
I also have an i3 3170t as server (with plex with NO tanscoding and as data grave).
as us see... my plan was to buy a x99 and 2680v3 cpu for streaming -> get rid of my i3 (cause i want a intel system as server) and use the x99 as server & streaming machine.
I hoped to reach Medium preset with this cpu.
Now u recommend E5 2686v3, E5 2699v3, E5 2696v3, E5 2698v3 and specialy 2696v3.
On ebay the cheapest 2696v3 was 340€ and its maybe an QS or even ES.
But 340€ is as much as i pay for the x99 + Ram + 2680v3 cpu. This is twice the money.
Do you think its rly worth it to go for the 2696v3 (single CPU cause a dual CPU is overkill & way to expensive i think) even its an qs or es for what i will using it?