So i did some testing.

and in big fights my gpu's are under utilised. im running on sli gtx 580's.im getting 120-130fps at warpgate both cards are at 100% load then great im happy.However at the crown my fps drops too 40-50 and both cards sit at 60% load or less (im still gpu bound at this point also) infact im pretty much always gpu bound 1920x1080 ultra settings except shadows on high.

soo is there still room in their code too make the gpu work harder or is that the limit for my cards? seems weird how they both go under utilised in big fights yet im still gpu bound.also turning phys x on murders my frame rate horribly it spikes from 30-120 constantly at warp gate even if I turn one card dedicated then its 30-70 spikeing

i7 3770k 4.6ghz
16gig ram 1800mhz extreme memory profile.
sli gtx 580's on current beta drivers(tried different drivers still same across all of them)

tried this in sli mode and single mode I just get less fps.changeing resolution and details dosent change the frame rate at all

This has been common knowledge for quite a while.

Everyone with a fairly balanced system gets solid frame rates at high GPU usage outside of major battles but drops to ~20-45 in large battles as the CPU chokes and doesn't send nearly enough work to the GPU. The GPU is thus half-idle because it only receives enough information to process a small portion of the frames it is capable of handling.

then surely it should show CPU when this happens. but in my case it does not its permanently GPU

That's highly peculiar and it should indeed indicate [CPU]. I had missed that line. I would chalk it up to an error in that system as you should almost never be GPU limited with 580(s) in large fights you're playing at 1.4 or 2.0 render quality and hitting a memory bottleneck. That or extremely strange SLI issues. 40-50 sounds just right for an overclocked 3770k in large fights hitting a CPU bottleneck.

I'm permanently on CPU but get alright FPS, its a bizarre phenomenon.

ive tried formatting a few times reinstalling drivers you name it.but this is the only game it chokes on skyrim 60fps constant 20-30% utilisation on boih cards borderlands2 is the same even with the crazy phys x it has.so it does have me scratching my head also

Its not that its underutilised, tis that keeping track of the 'entities' and 'physics' of a large battle e.g. where the derpers are and what their shooting is.

A. Very CPU intensive.
B. Hard to Mutlithread.
C. Not really what GPU's are built for.

hmm question. gtx 580's are pci-e 2.0 ive seen people using the 6xx series cards and being perma cpu bound.these cards are pci-e 3.0 think that is the culprit here?