Have the same card, and the new version is pretty slow, have both running side by side and its quite slower. At the office have a Quadro 6000 and is also a lot slower than LR 5.7.1 I don't think you are missing anything. It is just slow.
im having same issue like serious memory leak or over load and all im doing is trying to do minor adustment.
i have the GTX 970... a lot worst then previous version not sure whats up... after restarting 3rd time seems to work little better but after few photos starts to slow down and stutter....
Thank you all for the input, it seems no solution here from the user perspective.
But I still wonder, how such obvious issue went "undetected" before the release, as far I see is not related to one card, and the Nvidia TITAN X GPU does not stay in the minimum requirements stated by Adobe for Lightroom to get a reasonable working speed .
I still not purchased this version, I will stick with the 5 one until they will patch it.