[X370 TaiChi + 1700X] 1st build help. Temp, BIOSs

So all of my parts arrived and I have spent the day getting the system put together.  Still got additional drives to go in and cables to tidy (and buy so they can be better tidied).

As this is my first ever build, I'll be losing sleep over whether or not I applied the right amount of thermal compound and fitted the CPU cooler properly - that is the main concern.

I wonder if ya'll can help me out with a few things, make sure I understand stuff correctly.


Temperature

As this is an X CPU, I understand that there is a +20°C offset to the actual CPU temperature.  This would be reported as tCTL (including offset) and Tdie being the actual temperature of the CPU.

I'm on stock BIOS v2.20, and the UEFI "H/W Monitor" tab shows a CPU temperature that I come to understand maybe something along the lines of a sensor within the socket of the motherboard, and not the CPU itself.

I booted for the first time, no side panels on the case, case fan controller on high.  Ambient room temp of around 15°C ish.

UEFI H/W Monitor said ~33°C and climbing to about 35°C ish.

Took a look around in UEFI, played with some fan profiles, saw CPU fan speed change down to ~500rpm (Noctua NF-A15) on "silent" profile.  Set it back to "Standard" profile.

Rebooted and installed Windows 10 Pro (creators/latest iso) from USB stick.  Did not update. Have not connected to the 'net. Have not installed any drivers.  It's all vanilla Windows.

Chucked on HWInfo v5.56 (?) the latest as of earlier today, and Prime95.

Ran prime95 with the first option, just a CPU stress, no memory or other things.  Default options.

After about 30 minutes HWInfo said Tdie was 48.3°C !  tCTL was 68.3°C.

This seems awfully cool to me.  Even with the side of the case off, I am surprised.

Idle Tdie was around ~23°C, which strikes me a bit low.

I am completely new to Ryzen, my last system being Core 2 Duo E6750, which had a stock cooler.

Is there a change log so I can see what BIOS to update to, if I even need to?

I get the impression going to 3.10+ would give options for reporting CPU temperature from 'Socket' (source for older BIOS), Tdie or tCTL.

I don't really know what else would have changed that may actually help me.  I don't really intend to overclock, and if I did it would be something like p-states, as that looks interesting without losing the lower power consumption at idle.

Booting seemed to take a little while, not what I'd call excessively long but a good 30s or so.

I notice the motherboard code display showing all sorts of codes before getting on with showing the "press F2 or DEL to enter setup" screen.  From there into Windows it's quick.

Do I need to disable some kind of checking routine?  I think there was something in the RAM section or somewhere abouts in UEFI.

The "ultrafast" option I understand is something that one needs to jump through hoops to get to.  It apparently menas you don't get the about "enter setup" screen.  I'm sure someone posted some kind of guide to this but I can't find it.

Sorry for bundling multiple, potentially larger topics into one thread.

I'd be happy to break these out if people would prefer.  I guess my main question is - did I put my CPU cooler on right?

Cheers!

Ryzen 1700X

X370 TaiChi

Noctua NH-U14S

NT-H1 thermal paste (a squiggle splodge roughly size of cooked grain of long grain rice.)

Fractal Design Define R5

G.Skill Flare X 32GB (2x16GB) 2400MHz 15-15-15-39 (stock)

Zotac GTX 1070 Mini

Seasonic Prime Titanium 750td

Windows 10 Pro creators on Seagate 1TB HDD