Im not really sure why but my 2010 mac pro running HS with the 3.46ghz hex with 48gbs ram and a 512 raid 0 PCI SSD benches at 3200 15000, so on paper not bad.
I also have a dell workstation from 2013 rocking W10 2.6ghz hex 48gbs 1tb ssd it benches 2600 15000
https://www.cnet.com/products/dell-precision-t7610-mdt-xeon-e5-2630v2-2-6-ghz-32-gb-1-tb/specs/
You can see here the W3690 is quicker than the E5-2630
http://cpuboss.com/cpus/Intel-Xeon-W3690-vs-Intel-Xeon-E5-2630-v2
The dell is noticeably faster than the pro in pretty much all aspects of Adobe CC especially programs like lightroom.
I used an RX580 8gb in both and were running on 27" ACD.
Put the mac pro on a 23" ACD and it runs really smooth... 1920x1200 resolution.
Although the dell has a newer generation processor on paper the mac pro shouldn't be slower? Is this a mac OS vs Windows issue? Lightroom seems to run really badly on the mac, tbh ive never had lightroom work smoothly on any mac. All the usual settings have been optimized, previews set to 2048/medium and never to discard 1:1 previews.
Using sliders are very laggy on the pro even moving the exposure slider is like watching paint dry. Zooming to 1:1 is super laggy too.
It used to be the case that there wasnt really much difference between similar machines... but I dont know my experience so far is that CC is faster on windows but not as stable, more crashes.
I also have a newer dell twin xeon which is has no issues at all.
From reading through the threads I thought I would boot up the older back up machines to see what they were like. The dell is acceptable for use today. The mac is very frustrating indeed.
I purchased a base line 5k imac for my dad and that was also a frustrating experience in lightroom I would say its because its having to render 15mp of that display at 60fps every time you move a slider. Yet the 2017 15" macbook pro 2.9 i7 seemed to play pretty well but again a retina is about 2k so probably screen resolution.
The iMac pro even lagged a bit with sliders when I tried it at an apple store... That 5k display has a lot to answer for in terms of performance. Thats the frustrating thing apple dont sell a desktop thats relatively new that you can put your own display on...
Dont know if its a metal/open cl issue or the fact that CC isnt as well optimized for the mac... either way I dont think rocking the 2010 mac pro is feasible anymore.