CPU to GPU usage in Battlefield V at 1440p 144hz

So ive changed my setup yet again to see if above 60z gaming makes a difference in FPS shooters and I can certainly say im sensitive to FPS fluctuations.

Now ive played over 300 hours at 4k 60hz locked and ive just purchased a 1440p 144hz IPS screen to go along side it. my issue is...

depending on what settings im running in depends on what FPS I get (nothing new here but wait...)

ok so my PC specs

8700k @ 5.2ghz 

1080ti @ 1050mhz

16gb 3200mhz ram

970pro m.2

z390 aorus master

now my game specs at 4k

Everything on ultra where possible or on where possible

DX12 on

GPU restriction off

post AA on TAA high

res scale 100

Future frame rendering on

vsync on

this gives me a solid 60fps on all maps

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Now my game settings at 1440p to get a good balanced CPU and GPU usage.

Everything on ultra where possible or on where possible

DX11

GPU restriction off

vcync off

res scale 100

post aa on high

future frame rendering off

my results with 1440p i range from 50fps through to 90 fps on all maps....

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Now if I turn DX12 on this moves all the processing to the CPU and my FPS goes to above 190FPS but pins my CPU at 100% consistently and my GPU is only using around 16% to 35% at any one point. 

now ive tried playing around with numerous settings here and there to get 144fps with a balanced CPU and GPU load but still not managed to find the sweet spot without compromising on FPS. 

if I turn HDR on and switch my monitor from 8bit to 10bit it also impacts the FPS so I leave that off currently. 

any ideas? (turning on FFR doesn't help it only gives me lag and no frames)