*AMD has said that they are releasing a new BIOS to address the issues here on Sept 10th. Now we are waiting "2-3 weeks" for MB vendors to release new BIOS for their boards. You are welcome to post your results from your testing as we wait.
This Question/Topic is to consolidate Max Boost Testing/Results regarding the 3900x only. Please do not post if you cannot test a 3900x. If you have any advice on settings please post a pic of your test/results following the guidelines below.
Please only post results. This topic is for proof of results, not speculation.
Please post a picture of your test results if you can or cannot get your 3900x to boost to 4.6 on any core.
Please us Ryzen Master to view your cores. Select "Show Histogram" under Settings.
Be sure to click "Peak" in the "Histogram" section.
Please use either CPU-Z, CinebenchR20, or Geekbench for testing. Remember to run single core test.
Please list your Motherboard, BIOS version, and RAM speed.
If adjusted, please tell us if you used Ryzen Master, Bios setting, or another tweaking tool.
Please list your Highest Single Core MAX Boost
Your pic needs to include Ryzen Master and what test you are running.
If you can get a MAX Boost of 4.6 or higher then please post the information above and what settings you changed to get there.
Questions/Statements:
Why this forum?
There are many people who like many forums who have many different MB's. Everyone involved has an AMD CPU so this is the most common forums between users.
Well, if you (did you try to) adjust (overclock) X, Y, Z then it should work. (?)
Post a pic of your 3900x CPU max boost at 4.6 with the adjustment you advise.
Why these test?
There are common test that should test your MAX Boost. If you have another that will, then post it with a pic of your results. We want to duplicate your results.
Why Ryzen Master and not HWiNFO?
There seems to be a difference in reporting between Ryzen Master and HWiNFO. Ryzen Master is a first party software where as HWiNFO is a third party. I don't know which is accurately reporting so it is safer to go with first party until it is shown which is incorrect.
The images are small and hard to read.
Open the images in a "new tab" and you can view them at full size. If it's still too small, use "save image as" and view them in your picture viewer. If you just click on them they will pop up in a small window.
Example:
Cannot get any core to Boost to 4.6 on any setting. ALL set with Ryzen Master. MB: Asus Prime x570 Pro BIOS: ver 1005, RAM: G.SKill 3200c14. Highest MAX Boost: 4.350
Lastly, thank you to all who post results.
The userbenchmark data to start with.
There are over 10,000 benchmarks here with varying system configurations. Yet, the performance is relatively consistent across all samples (12.4% range, Gaussian distribution) regardless of the system setup used. Processors that overclock well, tend to have a much larger spread (26.4% on the i9-9900 for example). But try, as an experiment, to run your 3900X at stock settings, and then again with PBO enabled, and the OC cranked to +200MHz and PPT, EDC, TDC all elevated to motherboard limits. Do your single threaded scores change? For me, they do not. I'm not temperature bound nor are PPT, EDC, TDC stock limits reached in a single core workload. So why doesn't the processor just keep boosting? Because it has hit the FIT (voltage) limit. This limit cannot be removed without manual overclocking.
So increasing PPT, EDC, TDC or adding better cooling does nothing, because those weren't the limiting factors anyway. Raising those limits does affect the multicore score, as that tends to be EDC bound. After raising the EDC, it isn't long before hitting the FIT limit here as well. So you again, maybe 4% from what I see in all-core workloads, and again, you can probably get similar results with the included cooler (as users clearly are).
You can push the FIT limit up a bit with a higher scalar, but that really is risky. As the Stilt stated, the issue has nothing to do with the heat capacity of your cooling system, and everything to do with the heat density in a tiny 7nm IC.
BRILLIANT ! Enabling core performance boost and Performance enhancement (Level 3(OC)) on my board actually improved the boost duration !
Multi-core score is especially improved, by a good 200 points or so in R20.
Gonna check and see if only one of the options was necessary. - Dont need Core Performance Boost, just Performance Enhancer.
Cannot get any core to Boost to 4.6. Default set with Ryzen Master. MB: Asus Prime x570 Pro BIOS: ver 1201 ABBA, RAM: G.SKill 3600c16. Highest MAX Boost: 4.461
Did a number of test with Ryzen Master and HWiNFO with the new ABBA BIOS for my board. It's better but, I still can't hit 4.6. Depending on which reporting you believe, I come pretty close. With HWiNFO highest is 4,591.7. However, that number wasn't achieved with the test. It was hit as soon as HWiNFO opened. And, it's always the exact same number 4,591.7. If I hit the reset min/max/avg it will get back to that number on one or a few of my cores after a few minutes. That's without opening any programs or running any tests. I find it odd it's the exact same number to the decimal place every time.
The 4.516 was achieved while running the test.
There's still a discrepancy between reporting by each software. I'm still not sure which is correct. AMD updated their Ryzen Master on Sep 10th. They will also release a SDK on the 30th for other monitoring programs. However, it doesn't seem compatible with HWiNFO according to this. https://www.hwinfo.com/forum/threads/new-ryzen-3000-monitoring-sdk.5913/
Also, it seems that AMD was suppose to provide HWiNFO with something compatible but hasn't delivered yet.
Either way, I still can't hit 4.6 Boost. Though this is an improvement and honestly I would be fine with 4.591 if that was the case. But, I still don't know if that is what I'm getting.
*Odd thing while testing with Ryzen Master. Normally, during a single core test, only 2 cores are running the test by switching the work load. However, during this last batch of test, a 3rd core on my CCD1 became active and ran for a minute or so during the tests. Has anyone else noticed this?
Here is what "The Stilt" notes about voltages.
So for a manual-OC sticking at or below 1.325V should be fine for an all core overclock. 1.2V isn't going to hurt anything.
Updated to Windows Insider Fast Build 18995.1 and it appears to have improved threading performance. For single core, the load is staying on Core 0 now rather than bouncing between core 0 and core 2. Single core score now matches my manual score 
I can not get my 3900X to Boost to 4,6 GHz. BIOS & Ryzen Master on Default.
Cooler: H150i Pro RGB
MB: X570 Aorus Elite
BIOS: F12f (Agesa 1.0.0.4 B)
When enabling just 2 cores, they boost to around 4,55 GHz.
