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-   -   No more undervolting for intel based chips/mobos (http://www.rage3d.com/board/showthread.php?t=34052640)

xCLAVEx May 7, 2021 10:19 AM

No more undervolting for intel based chips/mobos

As suspected, Intel’s 10th-gen Skylake-based (6-8 core) chips in laptops are shipping with undervolting abilities disabled from some (if not all) OEMs. Well-known tech YouTuber Dave Lee reviewed his loaned MSI GS66. Among his criticisms were the build quality, price, and lack of ability to undervolt.

Until OEMs and Intel find ways of mitigating “plundervolt” without disabling a key feature of the chip that has become crucial on today’s thin, light, and undercooled notebooks, I cannot recommend purchasing any 10th-gen-equip systems if efficiency or performance are your main concerns.

Hopefully Intel will be able to produce a proper fix for this vulnerability that does not involve disabling undervolting, or I suspect they are going to lose even more market share to AMD.

Note: There is some great information linked in the comments regarding EFI modifications, so please check that out if this method does not work. Original post below:

I noticed that the temperatures on my XPS 15 7590 had been going crazy as of late. Instead of peaking at around 87C during mixed usage, I was seeing temperatures hitting 100C. At first I thought I had been the victim of rabbit hair and dried-out paste and so disassembled the laptop for a cleaning. After cleaning and repasting, however, my temperatures were still hitting 100C.

“That can’t be right”, I thought.

I checked my Throttlestop settings more closely, and lo and behold, my undervolts were all listed as 0.000mv. I recalled someone in my comments here on the Throttlestop guide had expressed a similar issue on their Dell G3 laptop, and then I remembered a security vulnerability that Intel had announced a few months back — then everything clicked. Dell must have silently pushed a BIOS update through Windows Update that disabled undervolting to mitigate the Plundervolt vulnerability.

Before we get into how to roll back the BIOS and re-enable undervolting, we should address whether undervolting actually needs to be disabled or not. The security exploit requires physical access to the machine, and so I think for nearly all home users, that already makes this something you do not need to worry about (enterprise might be another story, though). Intel left it up to the manufacturer for how to address this issue, and Dell cheekily decided they would push a BIOS update over Windows Update without telling anybody. That would be fine if undervolting wasn’t a literal necessity on the XPS 15 due to its thermal limitations.

So, how to fix this? Regardless of your manufacturer, you’ll need to find the next most recent BIOS update, download it, and re-flash the BIOS. For the XPS 15, that’s 1.5.0, but you can generally find this by looking at the most recent BIOS update listed on your OEM’s website, and lowering that number by 1 integer (e.g. if the most recent BIOS that disables undervolting is 1.9, try to look for 1.8).

You can’t just install the update and be done with it on the Dell, though. After the update finishes, press F2 to go directly to your BIOS settings. Here, you’ll need to reset the settings to the BIOS defaults. If you don’t do that, undervolting will not be available.

There’s one more thing you’ll need to do, which is disable for the ability of the BIOS to be updated through Windows Update again. Under the “Security” tab, look for the option “UEFI Firmware Update Via Capsules” and turn that off.

Once done, you can restart and your undervolt should be working again. Be wary of any additional BIOS updates, as they will almost certainly remove your ability to undervolt, and perhaps even re-flash.

Yep, no more ability to adjust the voltage in many cases. This is really bad because I (and many others like me) used to undervolt our processors to reduce heat and power consumption. Apparently intel/mobo manufacturers are locking the ability to adjust the voltage at the bios level.

The only "fix" is to go back to an older bios version and hope it allows you to adjust the voltage still...assuming you can even find an older one for your board (harder to do with laptops). If you can't find the older bios, you're pretty much SOL. I'm not even clear if this "security flaw" related to voltage settings is a flaw at the local level or if it can be accessed remotely. Even so, using a sledgehammer approach to completely disable the ability to adjust voltage on Intel chips is a very clumsy way to "fix" the issue because now we have even less control over our hardware.

EDIT: APPS like Throttlestop and Intel XTU don't allow voltage changes anymore so they become largely useless as that was their primary function.

xCLAVEx May 7, 2021 11:05 AM


Security Advisory from Intel
Unfortunately, our quest to bring easy-to-use Undervolting to the masses has hit a new roadblock. In late 2019, a security research team found out that agressive Undervolting (-250mV and further down, which is way beyond our limit) does not only cause Bluescreens - the resulting calculation errors can also cause malicious code to read memory addresses from the secured enclave of a little-known Intel system called SGX: Intel Software Guard Extensions.

Ever since SGX was introduced by Intel, it has always been disabled by default in our BIOS because there was little to no use for it. In fact, the only real-world use case that we have seen for SGX is playing copyright-protected Ultra-HD Blu-Ray Discs on your laptop. This is a very rare use-case because our laptops don't carry Blu-ray Disc drives anymore (although you could add one via USB) and most people who watch Blu-ray Discs (in the age of streaming service) use some sort of home cinema set-top box or gaming console for it.

(There might be other use cases for SGX in the industry that we don't know yet.)

Anyway, to be extra sure, Intel was not able to allow this go further. Since the SGX issue cannot be patched, Intel saw only once way to mitigate this issue. They recommended system vendors to not allow Undervolting anymore. This was published in the Intel security advisory INTEL-SA-00289 which received little to no attention in the mainstream press.

The public version of this advisory is very vague and only suggests end users to "update to the latest BIOS version provided by the system manufacturer that addresses these issues". But there is also a related, more detailed document which basically advises system vendors to disable all Undervolting hooks, including those that have previously been used by tuning software like Intel XTU before.
A bit more detail on what the issue is, which sounds like a rare and super situational exploit to begin with but certainly not worth the nuke and pave option that board manufacturers are adopting at intels recommendation.

Nunz May 7, 2021 12:12 PM

People make huge deals about these security flaws that don't matter for the every day user, so this is the result. Those people that made a huge fuss about Spectre and Meltdown, and then complained that performance was lost in order to patch in protection.. well pick your poison. I don't see the point in forcing the security protection on everyone; allow it to be disabled. I still use that program (forgot the name) everytime I reinstall Windows to disable the Spectre and Meltdown protections. Even if it's only 2-5%, I'd rather have the performance.

The patches make tons of sense for workstation and server users, but for the rest of us? Complete waste.

Trunks0 May 7, 2021 12:19 PM

God this is going to suck. Higher operating temps has already been an issue causing battery bubbling on Enterprise grade hardware from Lenovo and Dell with heavy Zoom users. Now where going to get even more because they are just going to operate hotter in general :rolleyes: awesome sauce.

xCLAVEx May 7, 2021 01:48 PM


Originally Posted by Trunks0 (Post 1338284283)
God this is going to suck. Higher operating temps has already been an issue causing battery bubbling on Enterprise grade hardware from Lenovo and Dell with heavy Zoom users. Now where going to get even more because they are just going to operate hotter in general :rolleyes: awesome sauce.

Yep, and this problem is going to become more apparent as time goes on and people start upgrading to more modern processors. They really should allow us to decide if we want the risk instead of unilaterally deciding for us and not giving us the choice.

I think on my board I can still lower the voltage manually in the bios, but I have NO idea how to do it correctly and don't want to mess up. For example;


"So if I want to undervolt by -100mv, I need to select the offset option and type in -100, or is it something like -0.0100 or do I just type in 0.0100 without the minus sign? This is where I get a bit fuzzy on the logic and can't seem to find any clarity on how it should work. "
Is pretty much my question (found on another sight where conveniently nobody replied).

metroidfox May 7, 2021 07:17 PM

In general all modern processors from both Intel and AMD run hotter than people are used to. They're just designed that way.

I figure any higher clocking ARM parts aimed at the desktop market also do the same at this point.

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