P: Slow performance on Xeon CPUs

My system is fully optimized. SSD NVMe, SSD normal, each project with a new catalogue, Win 10x64, 32 GiB DDR4-3000, LR CC 2015.9 and an Intel 6900k @ 4 GHz (8 real cores, 1100$-CPU).
Right now i'm editing a wedding. It is soooo slow and while Export you barely can do anything. Maybe two pictures can be edited then in one minute. This is not professionell.

Here comes a possible solution.
I'm always doing SmartPreviews sind 2015.6 (or so). And additionally sometimes 1:1-Previews.
I deleted all the 1:1-Previews, rendered the SmartPreviews again and... editing is fun again. OK, somewhat fun...
Let's see whats happening while exporting...

Seems that LR has problems when Smart- AND 1:1-Previews do exist.

Can you confirm this?

Same issues, xeon quad core, 16gb ram, ssd with plenty of space, x280 r9 gpu. 
Very slow to view 1:1s, regardless of smart preview settings, to switch between images, and refresh after making more than a few brush adjustments. Issues present for all of ver 6. Have updated to the latest via CC when available. Problem persists. Looking to switch to Capture One if not fixed by the time Sony release their A7rII replacement (currently shooting Pentax).

Rob, I'm confused - what's the "please add your vote on the link you have provided"? I'm not following where I'm supposed to vote on something, but do see your comment and their response on their FB page.

done

I put this on there Facebook:

Hi, Lightroom has a lot of problems on multi core computers. Please do something about it or let us users know that you are working on the problem.

With a link to this thread

They answered me with the Following:

Hi Rob, I would request you to please add your vote on the link you have provided, if already done we appreciate it.
I will surely pass the feedback to the team asking about the progress made on it. ~Tanuj

So lets all vote and post something on there Facebook >> https://www.facebook.com/Adobe/?rc=p

No one is gonna answer.  It's not on their radar yet, but if they get enough emails they might pick the story up and run with it. I'll email them again today.

Scott Gold,

I wrote to fstoppers 2 months ago. Was expecting some kind of answer, but untill now no answer at all. 

Welcome to the club! My advice is to write to Fstoppers.com and hopefully they'll pick up the story. Write them a quick message summarizing the problem and how Adobe is not addressing it. https://fstoppers.com/contact

That is not really the welcome I was wanting...but thanks! haha Submitted my request for fstoppers to research/write an article about Lightroom's lackluster performance on higher-end systems!

If we all just made some noise rather than sitting around hoping for someone to fix our problem we'd have this problem addressed and solved much sooner. Please, reach out to FStoppers.com and let's get some eyes on this issue.  https://fstoppers.com/contact

I've got a 8/16 core 6900K and a GTX1080 GPU and LR is as slow as molasses. I'm currently importing around 4,500 files and the convert to DNG and build 1:1 previews takes twice as long on my machine as it does on a slower spec'd late 2013 MacBook Pro with 4 cores. This is unacceptable.