Intel® NUC Elements
Support for Intel® NUC Compute Element, Board Element and Chassis Element
The Intel sign-in experience is changing in February to support enhanced security controls. If you sign in, click here for more information.
88 Discussions

Cant undervolt NUC9i9QNX after bios update


After updating the bios from the downloaded bundle, voltage offset is greyed-out(using XTU) and unable to be edited. i would like to keep the ability to undervolt the cpu, so it doesnt run at 90c as often as it does at stock settings. Do i really need to downgrade bios to give me that function?(

0 Kudos
1 Solution

I found out why intel removed all the features "unlocked cpu K" entails (PlunderVolt Can Mess With Voltages to Steal Intel Chips' Secrets), I can't deal with the lack of this feature and in light of this I will be returning the NUC - unless of course i can get my hands on a "qxcfl579.0034.ebu.exe"  BIOS

View solution in original post

18 Replies

I found out why intel removed all the features "unlocked cpu K" entails (PlunderVolt Can Mess With Voltages to Steal Intel Chips' Secrets), I can't deal with the lack of this feature and in light of this I will be returning the NUC - unless of course i can get my hands on a "qxcfl579.0034.ebu.exe"  BIOS

Super User Retired Employee

You cannot downgrade to that BIOS. Undervolting is no longer supported with *any* Intel processor, so it's not the NUC's fault.



why is the undervolting not supported anymore?

It worked fine with older BIOSs - and i was so dumb to update the BIOS to the "latest" 0061.

This is a NO GO for me - i will return the NUC9i9 and ask for a refund.

Super User

"why is the undervolting not supported anymore?"

Because it presents a security risk.

Doc (not an Intel employee or contractor)


how can undervolting be a security risk?

Wasn't it a moth ago or 6 moths ago or ...?

How come the latest XTU v7.4.0.26 is still having the puldown menu for changing the CPU offset voltage, but its disabled/grayed out?

Or is the security risk only for the NUC9 with an i9-9980HK?

This is a real PITA!


thanks for the info.

Still it doesn't exonerate Intel for not writing anything about locking an unlocked CPU in the description of the new BIOS - not the smallest hint. It should have been written in bolded Capitals.

The main reason to me for buying the NUC9i9 was the unlocked CPU - now it is locked.

Even bigger PITA, the BIOS is not downgradeable ...


Anyone from Intel care to comment?

Super User Retired Employee

Intel has disabled support for undervolting. This is across all existing processors and designs. It was the only mitigation for the Plundervolt! vulnerability that Intel was able to identify in the time available. For more information, see articles Plundervolt! A new Intel Processor ‘undervolting’ Vulnerability and What is Plundervolt! and How Does it Work? Could Intel have done better? Probably, but not in the timeframe in which a response was necessary.

I sympathize with folks that were using undervolting to correct an otherwise unacceptable thermal/acoustic situation. The fact is, however, that the *real* solution is to purchase a system (or cooling solution) that properly supports the thermal situation - and does so without acoustic penalty. That system (especially laptop) manufacturers are daily screwing their customers by providing only crap solutions borders on the criminal. Worse, they do slimy things like enforce system throttling settings for no other reason than to make their battery numbers (artificially) look better. Consumers, do your homework!

Ok, to your particular comments, I have no sympathy. You folks demand secure systems but then complain about the cost of having this security. Make up your minds. This cannot - and will not - be a selective thing. Either you want secure systems or you don't.

You cannot downgrade your BIOS because a security change was introduced. In particular, once the ME firmware is updated, you cannot downgrade. That's the rule and it is not changing. The chipset enforces it; it is not a NUC-level decision. If this means you return the NUC, so be it. Threats will not accomplish anything.

Just saying,



mr. Super User Retired Employee, you sure are entitled to have an opinion, but this time you should have kept it for yourself as it is way besides the point.
Judging by your wording i bet you don't even own a NUC9, but still provide "real" solutions?
FYI, the cooling solution of the NUC9 is very good. No one here complained about the cooling solution at full load but only about the behaviour of the fan(s) when the CPU is idle: the CPU temp is 45 to 50° but the fans still do 1450 RPM.
This has nothing to do with how capable a cooling solution is.

And no, i don't need your sympathy, as i didn't demanded a secure system.
I'm not working at the CIA, FBI or a military facility, I'm only a freelance software developer working at home.
On my NUC there's only my developement IDE with no internet or gaming.
With the undervolting the NUC was as silent as i wanted it when typing code.
But that's also not the point now.

When Intel identifyed an issue and solves it by disabling support for undervolting fine, but it should have warned the user
that an unlocked CPU will be LOCKED!
If i buy an i5 CPU i expect to get an i5, not an i3 and not an i7.
If i buy an unlocked CPU i expect it to stay unlocked after many BIOS updates.
Intel fooled me into buying an expensive machine with an unlocked CPU and with the new BIOS it is not unlocked anymore, meaning i can't undervolt but i also can't overclock.
What has overclocking to do with undervolting? Nevermind, i don't want your useless opinion.

I still wait for someone from Intel to comment.

Super User Retired Employee

Actually, I know exactly what I am talking about and I most-certainly do have a NUC9VXQNX system. Mine is mostly quiet; the chassis fans are responsible for what noise that I do hear and, with the current bugs in the way the EC runs these fans, undervolting is not going to make any difference to the system's overall acoustic penalties.

Let's be clear: Locked means the processor's base clock multiplier cannot be changed; nothing else. Your part is and remains unclocked. Don't make a claim that isn't true. Whether or not you can use undervolting has NOTHING to do with this. Undervolting *is* considered as being overclocking and would have voided your warranty regardless. Secondly, the disabling of undervolting is a universal happening, not specific to the NUC, and was well documented when the decision was made (do your homework better next time instead of whining after the fact). Finally, as I said, you cannot have it both ways. Intel must address everyone; you don't get to opt out. You cannot have security without some costs and this is one of them.

You get my considered opinion whether you like it or not. You asked for it when you started your badmouthing.



sorry Scott, I'm getting tired of your nonsens! You don't have a clue, as you don't have the NUC9i9 with an unlocked CPU.

Please stop wasting my time and the time of the comunity!

FYI, using the current XTU v7.4 NONE of the multipliers can be changed - I repeat, the multipliers are LOCKED.

The only settings that can be changed with the latest XTU is PL1, PL2 und the time - all 3 params can be set in the BIOS.

In conclusion, the latest XTU is useless.

I downgraded to XTU v6.5.1 and at first sight I believed that it saved my day, but no - now I can change the multipliers but only to a lower value as preset.

So mr. "I know exactly what I am talking about", please explain what "remained unlocked" from my i9-9980HK?

Don't bother, (as I have a crippled i9-9980HK, I know) - NOTHING remained unlocked!

Valued Contributor I

If you wanted an unlocked CPU, why did you buy a product based on mobile parts? Desktop CPUs can handle overclocking much better than a mobile CPU since you can have a large selection of cooling solutions to choose from using air or liquid. I agree that the i9 NUC runs a little louder and hotter than other NUCs but it is also a unique design.

Maybe return it and get an unlocked desktop if you need to undervolt or overclock your CPU. I have the same i9 and feel it works just fine for the size it is. Gaming does raise the noise level and heat but it does as well on my full desktop system.

One thing to consider with XTU is it is a general purpose tool. It will have features that do not apply to all CPUs. 

Valued Contributor I

Do you know what "K" means?

Does the i9-9880H exist?

Does Intel make both XTU and the i9-9980HK?

Did they work great together in the past, when we paid full price for our NUC9i9QNX?

On a related topic, how is that deal that is definitely still happening going with updated official Vega drivers for the NUC8i7HVK?


This whole situation reminds me of political fools that vote for a candidate based on their promises, watch as every single promise is broken and then do mental back flips explaining how their candidate is still absolutely awesome.

Super User Retired Employee

I was merely stating that the locked state has nothing to do with the microcode update that disables undervolting. If it was unlocked before the update was applied, then it should be unlocked after it is applied. If it is not, I am inclined to think it is karma.

Feel free to come back and ask questions again when you have learned to be civil. Until then, you are on your own AFAIAC.


Community Manager

Hi @garyd 


The Overclocking and Undervolting functionality was disabled for NUC9i9QNX starting with BIOS version 0059.

The reason behind this decision is based on the potential vulnerability issue disclosed in Dec 2019. In response to that Intel launched Intel® CPU Voltage Settings Modification Advisory that provides details about a potential security vulnerability only when Intel® Software Guard Extensions (Intel® SGX) is enabled on a system.

See also: Intel® Processors Voltage Settings Modification Advisory INTEL-SA-00289

We are working on a solution that would protect our customers from this potential vulnerability issue and allow the undervolting and overclocking functionality, but at this time these functions will stay disabled.

On the other hand, I cant provide you with BIOS version 0034 as you are requesting, and this is basically for the same reasons mentioned before, and even if you get a copy of this BIOS version, the system won't let you downgrade due to the security fixes implemented. Refer to BIOS release notes for further details.

I would recommend that you monitor the Download Center for updates.



Ronny G


Hi Ronny,


thanks for confirming the information!

For sure, you are entitled to change anything on future BIOS versions, based on whatever reasons you need to address.

But what you are NOT entitled is to change the behaviour of my computer (i bought it from you and now it's my property, not yours anymore), without my knoledge!

So for me, to make an informed decision about if i want to upgrade the BIOS, the description of it and the mentioned "BIOS release notes" should have contained, at least, the first two sentences of your post and written in capitals.

Even more if you know that a BIOS downgrade is not possible!

I have upgraded the BIOS and now one of the reasons for buying the NUC9i9QNX for a lot of money = the unlocked CPU is gone.

I'm not happy with my crippled i9-9980HK.

Valued Contributor I

Here is the issue, its Intel's own release notes:

BIOS Update Release Notes (

The "New Fixes/Features" makes no mention of "K" features being disabled whatsoever.

A microcode update that slightly impacts performance kind of stinks but it is what it is, this is an entirely different thing. This BIOS update converts the device into a lower tier device and makes no mention that this will happen.

Its more than a little annoying that Intel understands that this is niche product and the user base isn't strong enough to make a legal stink over this. If Intel released an update that un"K"ed the entire gen 11 lineup we all know what would happen.

"We downgraded your device without notice." would not fly in court but there is like 7 of us so who the hell cares.


Hello @BHarr8

Thank you for the information provided, we understand how this could affect your product so we recommend that you directly contact Intel Customer Support to check for warranty options (you cannot do this through the forums).

Here are pages where you can lookup contact information, including local/country phone numbers, by geography: 


Please keep in mind that this thread will no longer be monitored by Intel. Thank you for your understanding.  


David G  

Intel Customer Support Technician