Why does ArcGIS Pro have to be so slow???
I just did a Pro training course. For simplicity, I took our (admittedly elderly) dual 2.2GHz, 4Gb Windows 10 laptop. This has run Desktop (many versions) perfectly fine for years along with a suite of other GIS/DB tools, and seemed to work okay with some basic testing of Pro after installation.
Once I loaded up some tutorial data for exercises, it was agonising. 99+% CPU usage, most of the GPU and perilously close to thrashing page file (I shut down everything possible to shut down in Windows) running consistent 1.5-2GB RAM usage. It was basically unusable, 1-2 minute waits to do anything in Windows, and I could see Pro literally rendering every object second by second.
Sometimes it just gave up and said "meh, close enough for government work"
This was with a few tiny tutorial datasets and the web basemap/hillshade.
I didn't even dare trying 3D seeing as Pro was unable to even handle a file explorer dialog. After falling further and further behind the class simply because Pro does not run on a Desktop-capable computer, I gave up and ditched it for my workstation (2014 quad 3.4GHz, 16GB) for which is was fine, although the NVidia Quadro struggled a bit with frame rates in dynamic 3D.
Looking at what it was doing, I think Pro is spinning up a large number of background processes/services which eat up resources (geoprocessing handler, job handler, etc.) I could also see it dynamically building displays, panes and elements, sometimes rejigging them in real time as things opened and changed to get the desired layout, so there is a lot of work going on under the hood which is much more demanding and sophisticated than Desktop. Every time you click on something it is running through a whole set of rendering/workflow/data management dependencies.
For example even something simple like opening an attribute table. In Desktop, bang, open pane with first X lines, done. In Pro it was doing some kind of indexing, analysis, calculating different font sizes, column width etc to make it all 'look nice' before opening the table, and then of course depending on docking it had to resize multiple other objects and re-render them as well.
Short story: Unless you have a fairly new computer, expect that you will have to upgrade it to run Pro.
Replying to myself, how narcissistic! 
Ego aside, here's an update for those interested in the hardware side of Pro requirements. We're about to replace our Dell Precision quad-3.4GHz 16GB with Lenovo ThinkCentre hex-2.4GHz 16GB (don't ask why we are 'sidegrading', public service)
Of particular interest is the comparison between the 2014-era consumer Liteon 256GB SSD on SATA and the 2019 prosumer Samsung 500GB SSD on NVMe.
I won't go into the other benchmarks but they are roughly comparable as shown. As you can see above even though Passmark is just a synthetic benchmark, the performance difference between the two SSD models is dramatic, and remains the same regardless of the other hardware configurations (all Lenovos had the same class drive) as shown below.
This results in a smoother and more responsive experience in Pro, making up for some of the possible disadvantages of the system. Based on this and initial testing I would highly recommend adopting M.2 NVMe in your next scheduled upgrade. I still haven't rebuilt my gaming rig (shame, all I can run is Warframe. Badly) but I'll update you with the results, although that example won't be so clear cut as there's more variables beyond the primary drive being changed in support of *ahem* real-time dynamic rendered entertainment suites.
Finally, if you don't have the opportunity to move to NVMe and must stay with SATA (for example, you do not have M.2 support on your computer) be aware that even all 'standard' SSDs are not the same. Samsung (and others) are built with different tech it seems the big difference is that QLC ram in the Samsung QVO is cheaper but less durable than TLC ram in the Samsung EVO, max speed also drops.
Ref. "MLC vs TLC vs QLC: Why QLC Matters"
tldr: Replace your old SSDs with TLC-SSDs for maximum performance and durability. For Samsung this is the EVO gamerspec model, not QVO desktop model.
This article was not sponsored or endorsed by any of the manufacturers mentioned and remains my subjective and probably worthless opinion only.
Edit: Added world benchmark link for the Liteon in case you thought I'd accidentally benched my optical drive (yes the Dell Precision has one). Who knew Liteon SSDs were even a thing? Surprise! 
