Need Help - ASRock Fatal1ty B450 Gaming-ITX/ac Motherboard + Ryzen 5 3400G = High CPU Temps + 1.4V Core


Junior Member
Jul 20, 2019
Hello Everyone,

Hoping someone can help. I just built this ITX PC:

Mobo & APU mentioned in thread title
Noctua NH-L9x65 SE-AM4
16GB GSkill 3200MHz RAM
Samsung 970 EVO 500GB NVME SSD
Realan E-I7 case:
4 Noiseblocker NB-BlackSilentPro PC-P 80x15mm fans

This isn't my 1st rodeo when it comes to building PCs. I mostly build Intel, but this time decided to go AMD because I REALLY like the latest APUs.
I didn't use too much NH-T1 thermal paste & I checked to make sure the HSF is seated properly.

The issue: Getting high temps, just sitting in the UEFI (High 50C) & mid 40C to mid 50C just idlling at the Windows 10 desktop.
Running any kind of activity, like a windows update, spikes the temps to mid 60C's. Haven't even tried running any games yet. No overclocking.

I think the issue is in the BIOS/UEFI:
The H/W Monitor section of the BIOS shows CPU VCore Voltage: 1.424

When I originally went into the BIOS, I saw under the OC Tweaker section: CPU Frequency & Voltage > Voltage (VID): 1.4. 1.4 was in red, so I dropped it down to 1.1,
but the H/W Monitor section of the BIOS still shows CPU VCore Voltage: 1.424, even after I dropped it down to 1.1. So seems like the BIOS isn't reading my Voltage changes & is "stuck" on 1.424.

Also, CPUID HWMonitor software shows fluctuaion between 1.4-1.438 VCore under the CPU > Voltages
Under the Motherboard name > Voltages > CPU VCORE > it fluctuates more, between 1.136 & 1.44

BIOS is of course latest 3.30 version (first to support the Ryzen 5 3400G).

Anything i can try, or do I need to wait for ASROCK to issue UEFI update?



No Lifer
Aug 25, 2001
Hmm, I really wonder now. Because I've been having similar problems, but my R5 3600 CPU, is a 7nm chip, and your 3400G, is a 12nm chip.

But they both have similar issues, high idle temps, high vcore showing, hmm. Maybe immature BIOSes are treating them similarly, because they're both 3000-series? Sounds strange to me, but we know this release was a bit "rushed" to meet the 7/7 "deadline".

Hopefully, these things get cleared up for both of us, with newer UEFI releases.


Junior Member
Jul 20, 2019
I'm also getting memory access violation errors when playing games, so I can't play any. I'm assuming it's driver-related. I even did a fresh install of Win10 & it still happens. I've got about another week left on Micro Center's return policy. If this doesn't get cleared up by next weekend with either driver or UEFI updates, I'll probably return the APU & mobo & go back to Intel. Can't risk waiting that these issues will get iron out any time soon.


Senior member
Apr 20, 2015
I know your CPU is 12nm rather than 7nm but I am pretty sure it still has the same boost features as the other Ryzen 3000's. Basically, it will boost up to about 1.5 volts if the temps, current and total socket power let it. It reduces volts when it hits a load. If you reduce the voltage the chip compensates for that and boosts it back up anyway to make sure it stats stable. Setting lower limits for PPT or TDC/EDC is apparently a better way of lowering power usage if that is your concern.

You can also turn precision boost of completely and you will get WAY lower volts but you will be stuck at your stock frequency.

I would load bios defaults then either turn off PB(PBO is different) or stop stressing about the idle/low load voltages. Once you are sure thats working without errors turn your ram to XMP and make sure its still fine.

Both images are stock settings on my 3700x. I could probably up the PPT, TDC and EDC to the stock 3800x levels but am playing it safe until any kinks get worked out in my boards bios.


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Senior member
Jul 15, 2006
I'm curious about the way you figure out this, because I want to build something similar in same case, or smaller (Realan H80) and would be interested in your findings.

I would try the new bios-es from Asrock, they just released them yesterday, with AGESA 1003