I was one of the lucky few to be able to get hold of a Ryzen 5900X yesterday.
I installed the processor into my motherboard. Did a clean Windows 10 Pro installation including the latest chipset drivers from AMD.com and ran a couple of tests.
When I run Cinebench R20, within a few seconds, the CPU goes from 35 degrees to 87 degrees as reported by Ryzen Master. It never goes past 4.4Ghz. This can only be achieved if i set Ryzen master to Auto OC.
If I leave it at default, it does not go past 4.1 Ghz.
Single thread score of only 612 but multi thread score is about right compared to the published reviews.
Also, on a side note, the Ryzen power plan option does not appear, just the default windows options:
Asus X570 Prime-P (2802 Bios) DOCP enabled
Corsair Vengeance LPX 64 Gb 3600 Memory (On QVL list for board)
Dark Rock Pro 4 cooler (Kept Ryzen 3900X below 80 degrees in same scenario)
Edition Windows 10 Pro
Installed on 06/11/2020
OS build 19042.610
Experience Windows Feature Experience Pack 120.2212.31.0
Most of this is controlled by the motherboard so it could be the immaturity of the bios for the new chips on your board. If you suspect it is not behaving normally then I would start with a conversation with the support department of your motherboard's maker.
On the power plan did you load the new version of ryzen master? It has support for the new processors.
I am running this version:
Is it the latest?
I also updated the BIOS again to V2812
PRIME X570-P BIOS 2812
"1. Update AMD AM4 AGESA V2 PI 22.214.171.124 Patch C
2. Improve system stability
3. Improve DRAM compatibility"
No real improvements sadly
I think that is the latest. Here is a review on that processor from Gamers Nexus. You might want to compare to what you are getting. Looks like your results are about right to me.