Please remember that any mention of competitors, hinting at competitors or offering to provide details of competitors will result in an account suspension. The full rules can be found under the 'Terms and Rules' link in the bottom right corner of your screen. Just don't mention competitors in any way, shape or form and you'll be OK.
I'm quite sure you CPU is bottlenecking your CF5870 as it is (as in you are not getting full use out of them with the GPU usages not hitting close to 100%). If you are not having problem with your CF5870 (drivers or micro-shuttering), I would say you best sticking with it...and most definitely try to overclock your 1090T to 4.0-4.2GHz.Hi all is it best to stay with my 5870 crossfire setup or sell them for 1 single 7970 GPU.