it is your gtx970, if you get 8k@3x1080 of course your result will be lower then those with single monitor. 2600k is more than enough for AC especially if overclocked. The thing is, when upping the resolution you load the gpu more and the performance will suffer/will be bottlenecked so to say. The cpu load will get higher if your gpu is spitting out more frames, you cant test it buy running the AC performance app or MsiAfterburner at lower resolution/settings and you will see that when the frames are higher the cpu load/work will be higher as it must match the gpu and its high fps output. If you doubt me, look at my AC benchmark, I think you got 13k while I get 11k with a i7 skylake system but I guess I am running with higher settings than you.
AC VERSION: 1.9.3 (x64)
POINTS: 11046
FPS: AVG=75 MIN=43 MAX=138 VARIANCE=0 CPU=38%
LOADING TIME: 17s
GPU: NVIDIA GeForce GTX 970 (1920x1200)
OS-Version: 6.2.9200 () 0x100-0x1
CPU CORES: 8
FULLSCREEN: ON
AA:4X AF:16X SHDW:4096 BLUR:0
WORLD DETAIL: 5 SMOKE:5
PP: QLT:5 HDR:1 FXAA:1 GLR:5 DOF:5 RAYS:1 HEAT:1
Buy the way, here is my question. Have AC released a new patch or something as I was forced to lower reflection quality one step so that the video memory allocation of my gpu gtx 970 does not exceed about 3.5GB because of doing so the fps plummets down from 80-90 to 34. So have Kunoz upped quality of the gfx filters? And my ffb feels totally differently now, too. Feels more natural, so any one know if they have slipped a patch with out realising any info about it?
Earlier this year I used 1070 but it was totally overkill for AC so it went back to the store, now I almost feel like it was a bad decision as I have to downgrade my settings a step in game for smooth fps. AC Seems like when I played bf3 and bf4 when the each dlc made the game more and more demanding hehe.