bvideo
It would be interesting to find out why the 1800x system glitches at a lower CPU %. DPC compared with the 6850K? Too many registers to save/restore on interrupts? Reaper not optimized for 1800x?

DPC Latency was low/consistent... so that's not the culprit.  
 
Reaper is not fully optimized for the 1800x (no DAW app currently is).
I doubt it would make that significant of a difference.
I chose to test with Reaper... as it makes very efficient use of multiple cores.
 
FWIW, I think it's just down to the Ryzen architecture not being particularly well suited to processing multi-threaded applications at low-latency.  
Where low-latency isn't a factor (video rendering), Ryzen performs well.
 
Scan in the UK tested Ryzen and came to the exact same conclusion.
 
6850k craps out ~99% load.
7700k craps out ~95% load.
1800x craps out ~93% load.
 
 

The other things specific to Ryzen that stands out for me is power consumption. Single core performance of the 1800x is almost identical to my 2600K. Identical power consumption, although the 1800x has twice the core count. BIOS can play a lot into voltage on the CPU so makes me wonder how much of the variation stems beyond the Ryzen itself.

Get on my CPUs level!

I see Jim is a builder of Intel machines and so does have an agenda.
The math processing I would expect to be a direct Correlation to MIDI.
And in the real world there would be 6 or so VST's per  "real track".(Not blank)
and so a real world test, in a  (Better developed) studio IE -Pro Tools, Cakewalk, Cubase,of loaded audio tracks alternating with  MIDI tracks ... Might  revile 8 cores to be Superior to 6... and 4 cores @ 4.2 to much more quickly over heat.
 
However , I'm quite sure a Ryzen 1700x would be more than I would ever need.> (Around $360)
{and as a bonus , AMD boards  generally go for $100 less than Intel}
 
The down side is No Thunderbolt option , However RME is pro.

I've found Jim to be a straight shooter on his many posts on here and his helping users.  I don't think he is on a "Intel only" mission.  If you don't agree with his test results do them yourself and report back. 

FireBerd
I have an (older) intel my self.
It’s Jim who says he is on the Intel Train. (See Jims link above)
Yes, I wish I had the resources to build 3 machines to test myself…So I like most rely on comprehensive test like the Benchmark scores collected from hundreds of persons  confirming the performance/Value of the Ryzen series processors. See>www   cpubenchmark.net/high_end_cpus.html
 
{I do not doubt Jims results- If anyone (Using "Reaper") feels the need to have a couple hundred tracks of nothing, with only 1 VST on each and NO MIDI...Intel is the way to go.}

Jim use to make AMD machine when they had a competitive product. Jim has no agenda.
The new Ryzen chips from AMD for a small home studio that uses the machine for video editing too would
probably be better then Intel machine.
The Ryzen chip performs very well, just not at super low ASIO buffer lsetting ike an Intel I-series chip does.
 

Bill Gabbert
FireBerd
I have an (older) intel my self.
It’s Jim who says he is on the Intel Train. (See Jims link above)
Yes, I wish I had the resources to build 3 machines to test myself…So I like most rely on comprehensive test like the Benchmark scores collected from hundreds of persons  confirming the performance/Value of the Ryzen series processors. See>www   cpubenchmark.net/high_end_cpus.html
 
{I do not doubt Jims results- If anyone (Using "Reaper") feels the need to have a couple hundred tracks of nothing, with only 1 VST on each and NO MIDI...Intel is the way to go.}

This is humerous...  
 
I've been building DAWs professionally for over 20 years.
We have no agenda... except to build the best possible DAWs for our clients.
We've used Athlon CPUs in the past (when they were out-performing Intel).
Had Ryzen 1800x performed superior to the latest Intel 7700k, 6850k, etc... we would have happily used them.
Had the 1800x lived up the the hype of performing nearly identical to the 6900k (at half the cost), it would have been great for our clients (and for business).  
For working with low-latency audio, based on audio specific stress-tests, this is not the case.
 
We use Intel CPUs... because (right now) they're the top performers.
If the 1800x lived up to the hype (for low-latency audio), why would we pump Intel at the cost of losing business? The short answer is... we wouldn't.
 
Even if the 1800x performed identical to the 6850k (both $500 CPUs), that's not enough of a reason to go AMD.
You forgo Intel USB, Thunderbolt-3 with full "PCIe via Thunderbolt support, etc.
 
If the 1700x or 1800x is enough CPU for you... more power to you.
We're building professionally.  Clients want the best possible machine.
I'm on the "Intel Train" because it's the best performance choice for myself and our clients.
If you were paying someone to build your next DAW... and going with a $500 CPU, would you want the top-performer, or would you be OK with a CPU that's "good enough"?
 
The proof is in low-latency audio specific stress-tests.
If/when AMD is outperforming Intel (running heavy loads at a 32/48/64-sample ASIO buffer size), that's when we'll use AMD.  
 
 
 

InstrEd
The Ryzen chip performs very well, just not at super low ASIO buffer lsetting ike an Intel I-series chip does.

Bingo!

I'll tell you what...
I'll assemble yet another Ryzen 1800x build... and I'll max out the RAM speed.
I'll report back with the numbers.