Question Intel blocks undervolting - Reddit

[VirtualLarry]

https://www.reddit.com/r/intel/comments/10slejm

Interesting read. Seems to be a response to Plundervolt, yet fraught with peril.

 

[Doug S]

Oh great, another thing I will have to look out for when I look to build a new PC later this year, and another reason to look at AMD unless they feel a need to follow (i.e. make people pay for more expensive low TDP SKUs instead of getting them for "free" by undervolting something with 65 or 95 W TDP)

 

[mikeymikec]

So let me get this straight, feel free to correct me if I'm wrong...

A vulnerability in a feature that Intel removed/disabled in series 11 is the reason they disabled undervolting in series 12 and 13?

I'm kinda hoping that I've misunderstood because this makes no freaking sense. It sounds like the wood for the stable was taken to build a barn after some horses escaped and now they're taking the roof off the barn to make sure no more horses escape the stable.

 

[In2Photos]

I have a Dell XPS15 laptop with an i7-9750H in it. The fans on this thing would go nuts anytime I was plugged in and even basic tasks were being performed. And I wasn't the only one with the issue. I saw where people suggested ThrottleStop so I gave it a shot. No go, Dell had disabled it via BIOS updates at Intel's request. So I rolled back the BIOS manually and disabled auto updates so I can use ThrottleStop. It helped, doesn't completely solve my fan issue, but reduced the number of times they ramp up.

 

[moinmoin]

Refresher:

Plundervolt

According to a student's bachelor thesis AMD simply isn't affected, though that may be more due to its SMU being under-documented. The conclusion explains well what Plundervolt relies on on Intel chips to work.

"During testing on the Ryzen 5, not a single fault on the operation being run was ever observed. A possibility is that Zen CPUs possess larger capacitors, such that timing constraints are always met in Zen, allowing logic gates to always hold their correct values for the duration of their timing constraint. Another possibility is that Intel Hardware is more power optimized. An observation made while testing was that the idle state on the NUC was usually around 685mV, which is substantially less than the 900mV of the idle P-State. If the Intel core simply require less power to function in general, the threshold where a bit flip occurs can may reached without the entire system freezing, while this threshold is simply not reachable on Zen CPUs. Finally, control may not be fine-grained enough via the manual OC interface, as the power commands aren’t directly sent to the CPU, but to the SMU which then updates the power supplied.

The greatest challenge may have been the limitations of the manual OC interface: one can only specify a discrete set of VIDs that can be run, making it a lot more difficult to hit the exploitable voltage window (Fig. 2.4). From Skylake onwards, Intel Chips possess an external voltage regulator that also takes a VID, but in 5mV steps, while the MSR 0x150 allows steps of 1/1024 V [MOG+20, 3], meaning that one can set a far more precise value using the offset in the MSR than when directly using the VIDs. Whether an equivalent MSR or other interface exists for AMD Zen is an open question. Much about the functionality of the SMU is still unknown.

Finally it is unclear if the bitflips observed may not simply be a quirk of Intel’s ALU. As their CPUs are extremely homogeneous, it is not surprising that the same behaviour is observed across different CPU types and Microarchitectures. As described in Section 4, a bitflip occurred at around the same position at every fault for sufficiently large operand values or the most significant bits would flip if the second operand was smaller than 0xff, in other words, it is possible to reliably produce an error at the same locations in a calculation. On the other hand, not a single fault was produced on the Ryzen. Control over voltage may simply not be fine-grained enough."

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XMG's timeline is also insightful:

https://www.reddit.com/r/intel/comments/10slejm/_/j73ge9a

 

[IEC]

I have a Dell XPS15 laptop with an i7-9750H in it. The fans on this thing would go nuts anytime I was plugged in and even basic tasks were being performed. And I wasn't the only one with the issue. I saw where people suggested ThrottleStop so I gave it a shot. No go, Dell had disabled it via BIOS updates at Intel's request. So I rolled back the BIOS manually and disabled auto updates so I can use ThrottleStop. It helped, doesn't completely solve my fan issue, but reduced the number of times they ramp up.

Same issue on a Dell G15 11800H laptop. They have it locked down tighter than a welded lug nut. And not just the CPU - can't adjust the TDP of the GPU manually either. Sure would love being able to choose something intermediate between 40W and 115W for noise optimization and longevity reasons. Instead have to enforce the "Silent" mode in the BIOS to artificially cap GPU power to 40W just to run at acceptable noise levels when gaming (e.g. when traveling). No undervolting of CPU or GPU possible. Afterburner doesn't work. The Alienware OC tool is locked to only Alienware models. Sad.

Repasting the TIM and undervolting my 6700HQ laptop made noise levels way better and it barely ramps under normal usage. Also a Dell model, so how much more locked down the new Dell is surprised me. Next laptop will almost certainly not be a Dell.

 

[WelshBloke]

I have an XPS 13 with a 10th gen (I think, I'll check when I get home) i7 in it and the fans on that ramp up like crazy and it runs warm. But that's only under windows. Running Ubuntu it makes nare a sound unless I really load it for ages.
Like you guys say the bios is pretty locked down so Linux must be doing some powerplan magic there.

 

[fusionTi]

Same issue on a Dell G15 11800H laptop. They have it locked down tighter than a welded lug nut. And not just the CPU - can't adjust the TDP of the GPU manually either. Sure would love being able to choose something intermediate between 40W and 115W for noise optimization and longevity reasons. Instead have to enforce the "Silent" mode in the BIOS to artificially cap GPU power to 40W just to run at acceptable noise levels when gaming (e.g. when traveling). No undervolting of CPU or GPU possible. Afterburner doesn't work. The Alienware OC tool is locked to only Alienware models. Sad.

Repasting the TIM and undervolting my 6700HQ laptop made noise levels way better and it barely ramps under normal usage. Also a Dell model, so how much more locked down the new Dell is surprised me. Next laptop will almost certainly not be a Dell.

My work laptop is an XPS 15 with an I9-10885H. Yes, the ridiculous pushed to the max top-of-line Comet Lake mobile CPU. I've pretty much accepted constant fan noise and a stream of heat as there is no way to have a middle ground between extreme heat max performance or the "silent" BIOS that kills performance. I've also never seen it boost above 5.0Ghz which was supposed to be the whole point of this stupid Comet Lake garbage.

 

[Markfw]

My work laptop is an XPS 15 with an I9-10885H. Yes, the ridiculous pushed to the max top-of-line Comet Lake mobile CPU. I've pretty much accepted constant fan noise and a stream of heat as there is no way to have a middle ground between extreme heat max performance or the "silent" BIOS that kills performance. I've also never seen it boost above 5.0Ghz which was supposed to be the whole point of this stupid Comet Lake garbage.

You do have an option now... Zen 4.

 

[fusionTi]

You do have an option now... Zen 4.

That is incorrect, my option is ask IT for a new laptop, where they would give me a crappy Inspiron with a 2+8 Alder Lake-U processor like they are giving out to everyone right now. This isn't a computer I bought myself or else it would have been Zen...

 

[Accord99]

How is AMD an alternative on mobile when you can't undervolt them either?

 

[Markfw]

How is AMD an alternative on mobile when you can't undervolt them either?

I don't know if that is true or not, or if you even need to.

 

[alcoholbob]

I updated my Z790 BIOS recently and interestingly I see my voltages are indeed higher. My 13700K with a -130mv undervolt used to max out at 1.245V in synthetic tests on the launch BIOS, now it maxes out at 1.296V at the same settings. I can keep jacking up my undervolt in the motherboard BIOS but it just straight ignores whatever I put in.

Interestingly, my PC used to crash while trying to load Windows at -150mV undervolt. Not I can set to -200mv, -250mv, it doesn't matter, I always post and get into Windows, and the motherboard just seems to ignore whatever undervolt I put in. At these higher voltages, minor 130-140W transients at the desktop used to only push my CPU to around 65C, now it's going into the 80s at peak temps.

Because my voltages are just through the roof now at stock, I decided to overclock my 13700K to 13900K speeds. Might as well, it barely adds to the voltage anyway as I can't run lean and low powered any more, as pushing from 5.3 to 5.8 only gets me to around 1.324V on my current system.

 

[TheELF]

Oh great, another thing I will have to look out for when I look to build a new PC later this year, and another reason to look at AMD unless they feel a need to follow (i.e. make people pay for more expensive low TDP SKUs instead of getting them for "free" by undervolting something with 65 or 95 W TDP)

1. "Intel states that the undervolting will still be available from the BIOS and is not affected by the new Undervolt Protection feature"
2. You can have extremely low TDP with very high Vcore. Vcore affects only heat with everything else being equal and on a low TDP system there is no need to worry about heat.

So let me get this straight, feel free to correct me if I'm wrong...

A vulnerability in a feature that Intel removed/disabled in series 11 is the reason they disabled undervolting in series 12 and 13?

I'm kinda hoping that I've misunderstood because this makes no freaking sense. It sounds like the wood for the stable was taken to build a barn after some horses escaped and now they're taking the roof off the barn to make sure no more horses escape the stable.

Intel is probably just fed up with reviews showing them using 300+ W "out-of-the-box" or "at default" if this allows them to cement their recommended settings being different from full blown balls to the walls settings hte mobo makers use then it explains it all.

"The other interesting detail is the so-called "Recommended Settings" from Intel. Every new SDK have them for obvious reasons. That's a good starting point for firmware developers. And in the new recommended settings, the Undervolting Protection is enabled by default. "

 

[gdansk]

Intel is probably just fed up with reviews showing them using 300+ W "out-of-the-box" or "at default" if this allows them to cement their recommended settings being different from full blown balls to the walls settings hte mobo makers use then it explains it all.

That's a totally different issue and Intel could put a stop to such high out of the box power limits any day if Intel thought that was a problem. But they don't care because it benefits them.

This issue is all about some changes being made to reduce the impact of a vulnerability. A vulnerability that doesn't seem to impact their competitor's parts. The changes are mainly targeted at business laptops. And Intel is leaving it to the discretion of the OEM if they want to enable undervolting options or not in the BIOS. This is a step back for consumers, who should always have that option if they understand the risks.

 

[TheELF]

That's a totally different issue and Intel could put a stop to such high out of the box power limits any day if Intel thought that was a problem. But they don't care because it benefits them.

If they would outright force everybody to use specific settings it would turn into a media circus.
Intel is going to avoid something like that like the pest.

And Intel is leaving it to the discretion of the OEM if they want to enable undervolting options or not in the BIOS. This is a step back for consumers, who should always have that option if they understand the risks.

If the OEM has the choice then how is that a step back for consumers?! The consumer just has to do their research and get a mobo that supports it, someone that understands the risks can also understand the need for the additional legwork.

 

[In2Photos]

If the OEM has the choice then how is that a step back for consumers?! The consumer just has to do their research and get a mobo that supports it, someone that understands the risks can also understand the need for the additional legwork.

Unless, of course, the OEM releases a BIOS update that no longer supports the function.

 

[DrMrLordX]

This story is not new, and it seems that some OEMs are going to disable undervolting in the UEFI in keeping with XTU.