（技术贴）关于降压对处理器的影响的系列讨论（是否损害cpu）转

（技术贴）关于降压对处理器的影响的系列讨论（是否损害cpu）转介绍

转载自贴吧

以上全是百度贴吧观念，与本站无关，有任何问题，恕我们不服任何责任，谢谢。

https://tieba.baidu.com/p/5856889377?share=9105&fr=share&see_lz=0&sfc=copy&client_type=2&client_version=10.1.8.1&st=1556445997&unique=80104363896340815DA204EF732FDEE8

前段时间我撰写了一篇关于通过降压降低发热来达到增强性能、降低功耗以达到更长续航的技术贴（传送门：http://tieba.baidu.com/p/5853261036?pid=121630554469&cid=0#121630554469），文末交代：“.网上有传言说长期降压使用会导致cpu缩缸，也有人说不会，......，如果得到准确的答复，我将另开一贴详论此事。”现已得到多方消息，我将其汇总给各位吧友呈上。

还是那句话：本文纯手打，如有转载请注明出处。更新可能较慢，烦请大家理解。其间有大量英文（国外大佬的话），我会提炼其中的精华，将其用人话阐释出来

（一）我与Intel美国总公司在其官方技术论坛上的对话（英语不好大佬别笑）：
我：I am a customer using Core i7-8550U cpu.As you can infer from the model of the cpu I use,I am a laptop user.Compared with the desktop systems,the cooling systems of laptops are generally more inferior.So the performance of laptop's cpu is always strictly restricted by the Thermal Throtting.In order to decrease the heating,I use Intel Extreme Tuning Utility to offset the core voltage to lower the temperature ,thus boost the performance.It does work!Before the voltage offseting,the cpu could only stay on a frequency of 3.28GHz when using the cpu-z to stress it and its mark is about 1800 in the long run.But after the voltage offseting ,it could stay on 3.71GHz and in cpu-z its mark is 2200!!!What's more, the package TDP even drops a little.That means the laptop would be more power saving!!!So many advantages have been listed,but my worries and questions come:rumor has it that if you offset the core voltage for a long time,especially when it is under its full capacity(like Turbo Boost),it would damage the cpu!And after maybe a few months,you would find your cpu can't reach the original frequency(for me,it's 3.99 or4.00GHz) even in Turbo Boost in its default voltage.That's because part of the cpu current is damaged by the strong current caused by the voltage offseting!Is that true?Can I offset the voltage of my cpu in order to save power,cut down heating and finally boost the performance without damaging my cpu?

INTEL：Hello, GJC. Thank you very much for contacting the Intel Communities Team. I will be more than happy to assist you.

Firstly, allow me to mention that the Intel® Extreme Tuning Utility is intended for unlocked/overclockable processors only (cf. Intel® Extreme Tuning Utility Download, supported products section). Then, the risk of changing the default settings of the processor is too great and the results may vary.
Please keep in mind that Original Equipment Manufacturers (OEMs) might modify some features in your processors as its convenience so we do not recommend performing this modifications with mobile processor.

I recommend you to get in touch with your OEM so they can let you know if there are settings that you can manage in order to achieve the configuration you are looking for.

Antony S.

我又追问：
I'm very glad to receive the reply of you,Intel.

Firstly,I do understand the Intel® Extreme Tuning Utility is specially designed for unlocked/overclockable processors,but it can also customize the performance of other cpu which is not unlocked or overclockable.Secondly,as to this sentence:"the risk of changing the default settings of the processor is too great and the results may vary",what are the results or the risk?Is it something about software like:the crash of system or blue screen or is it something about hardware(my cpu)like:damage the cpu,making it unable to carry on the calculation as it was designed just like I have mentioned or even burn the motherboard?

Looking forward to hearing from you soon.

GJC

INTEL：
Hello, GJC. Thank you for your response.

Regarding your questions:
The Intel® Extreme Tuning Utility was designed for unlocked/overclockable processors since these units are optimized to support overclocking. Frequency or voltage changes should not be performed to other processors that are not designed for it. Performing these changes on incompatible platforms are under the responsibility of the user.
There can be several results like system crashes, system instability, performance issues, hardware damage, etc...
Antony S.

我继续刨根问底，直接抛出最关键的问题：
Thank you very much for your patience,Intel.

You have answered most of the questions that I have put forward.But there is one more most important question that I want to figure out:Is offseting the voltage properly (that means not making the system unstable) harmful to the longevity or the health of the i7-8550u cpu？

Looking forward to hearing from you soon.

GJC

Intel却再也不说话了。。。

翻译成人话（两方的内心OS）：
我：我发现用XTU降压i7-8550u有XX、XXX、XX......等一堆好处，但是降压对cpu有伤害吗，会缩缸吗？

牙膏厂：1.XTU是专门设计给带K的处理器用的，不带K的不要瞎用!
2.不按我的设定玩风险太大了，我也不确定后果
3.OEM自己会调教cpu，你不懂别瞎玩（mdzz，OEM调教你就不提风险了，我自己调教就说风险大，说的好像OEM就会按你的设定玩一样，你说TDP是15W，X1的TDP不照样拉到了29W吗？）
4.有需求请联系OEM（说的好像美帝良心想会理我一样）

我：1.我知道XTU是专门设计给带K的处理器用的，但你看我不照样可以在8550u上调电压吗？
2.你说有风险，风险是什么？蓝屏？死机？还是缩缸？主板烧坏？

牙膏厂：1.我TM再说一遍：XTU是专门设计给带K的处理器用的，不带K的不要瞎用!自己作的死出了事要自己负责！！！
2.有”可能“会有系统不稳定，死机，性能，硬件的问题（注意原句的“can”这个词用的很微妙，其表示客观的可能性，这话说的简直和天朝外交部有时说的话一样，等于没说）

我急了：你就告诉我适当的（不影响系统稳定性的）降压对8550u的体质和寿命TM到底有没有影响与危害！！

牙膏厂：（跑......）

Intel为什么不愿意回答我最关键的这个问题，请大家自己做出判断。我本以为这事情会不了了之，但是这时论坛里有位叫N.Scott.Pearson的大佬开始帮我了，这个N.Scott.Pearson是谁呢？我查了一下：他是一位刚从INTEL退休的高级软件工程师（牙膏厂内心OS：***雇佣了你大半辈子，现在你退休了开始给我捣乱了啊？！），算是个大佬，同时他也就“为什么Intel不愿意回答我最关键的这个问题”做出了分析。（这是他的领英：https://www.linkedin.com/in/n-scott-pearson-911120128）

（二）N.Scott.Pearson与我的对话：
N.Scott.Pearson：
Intel is likely not going to answer that specific (can of worms) question - so I will. Offsetting the voltage positively can have long-term affects on the lifetime of the processor. Offsetting the voltage negatively should not have any long-term affects on the processor - presuming this offset is small enough that it doesn't affect stability.

Hope this helps,
...S

我：
Thank you, N.Scott.Pearson

I do hold the same opinion like yours. But you know,I want an official confirmation(or an adverse opinion against it) from Intel which can eliminates the worries a nd puzzles of me and my colleagues. I and my colleagues are working on laptops,which can boost the performance of cpu through negatively offsetting the voltage of cpu properly. So I'm eager to have a definate answer about it.

GJC

N.Scott.Pearson：
Unfortunately, I rather doubt that you will get one. Intel does not officially condone overclocking (and offsetting the voltage is considered overclocking), so they may not be willing to say that this is ok. Still, if you would like to wait for such a response, feel free to do so.

...S

翻译成人话：
N.Scott.Pearson：牙膏厂是不会理你的，所以由我来捅他一刀子

。给cpu加压对u的体质和寿命是有影响的，但是降压对u的体质和寿命毫无影响（只要别让系统不稳定出幺蛾子就行）。

我：
我知道，可我就是要牙膏厂他看着♂我的眼睛♂，亲口认真的许诺我

，说没（他）有（爱）影（我）响我和我的基友才放心

N.Scott.Pearson：
你活在梦里（他根本就不♂爱♂你），牙膏厂官方态度是不支持、不允许超频的，所以他也不会允许你对他的cpu做任何电压上的改动

从N.Scott.Pearson的回答基本可以看出，降压是不会损害cpu的。可是他毕竟是高级”软件“工程师，再说一家之言不可信，兼听则明，我在知乎搜索一圈之后发现一无所获（说实话某乎真要谈学术问题却反而没人），于是就求助于Quora（现在好像也被墙了）。在Quora上得到了一位叫Paul Ledak的回答，这个Paul Ledak是谁呢？我又查了一下，他是IBM的全球微处理器制造部门的副总，2015年刚刚退休，这位可以说的上是巨佬了。（他的领英：传送门：https://www.linkedin.com/in/paulledak）

（三）Paul Ledak对该问题的理解：
Paul Ledak：

Undervolting your CPU is completely safe. There is no physical/electrical mechanism associated with undervolting that can cause damage to your CPU. However. there are some things you should know and be aware of when you are undervolting your CPU.
When CPUs are manufactured, there are variations in the manufacturing process that produces CPUs that can achieve different maximum clock frequencies… i.e.. some are faster and some are slower than others. The manufacturer tests these CPUs…. finds which ones are faster and which ones are slower… labels them and sells them at different prices… even though they may have all been produced exactly the same. However, when they say that a CPU will work at a certain frequency, say 2 Ghz, this really means that they have tested that the chip will work at this frequency plus some margin of error (say 10% or 2.2 Ghz (I cannot say what margin of error Intel uses in its manufacturing test)) at the worst case operating voltage and the maximum operating temperature.
It is important to note that worst case operating voltage is the LOWEST voltage that the processor is spaced to operate at as in general, the lower the voltage…. the lower the operating frequency. Additionally, note that the highest operating temperature as the hotter the CPU is, the slower it runs. CPUs when first turned on typically operate at room temperature (or about 25 degrees C) but are typically speced at a maximum operating temperature of 85 degrees C (or sometimes hotter). If you could somehow keep the processor closer to 25 degrees C, it would certainly run at a higher clock frequency than if it heats up to 85 degrees C.
So what happens if you undervolt the CPU. First, you are reducing the maximum operating frequency of the processor. Depending on the processor and the voltage change, for example, you might change your 2 Ghz processor to a 1.8 Ghz processor. However, remember that the manufacturer really tested this processor to work at say 2.2 Ghz, having some margin of error. So, your 1.8 Ghz under voltage processor probably is still a 2 GHz processor… but with little margin of error. The only way to know how low you can lower the voltage and test to see if the computer keeps working.
So what is the best way to test how low you can lower the voltage to see if the computer is still working? One obvious test which is a very BAD test it to simply boot the computer. Of course if you lower the voltage and you cannot boot the computer than you have definitely lowered the voltage too much. But if you CAN boot the computer, this DOES NOT mean that you will have a functioning computer. Why? Because when you boot the computer, your processor is probably running at a cool 25 degrees C and is therefore running in its FASTEST thermal operating zone. So, in order to know if your computer will be reliable at the under voltage, you have to have the computer running under some more extreme conditions, where the processor is working at its hardest and generating the maximum amount of heat… and for a sufficiently long time to get the processor up to its maximum operating temperature… around 85 degrees C. If the processor still runs at this temperature than you have found a safe under voltage to us. Some applications that might do this are video compression, 3d rendering…
There is an additional complexity that you may also have to consider depending on the processor and laptop you are using and the options available in the Intel’s Extreme Tuning kit. One feature that some laptops use is a temperature sensor on the CPU and an automatic throttle back in the CPU clock frequency when the processor starts to get too hot… thus allowing it to cool down a bit before it brings the clock frequency back up. This obviously adds some complexity, but may also help your processor to stay running at the lower voltage by not allowing the processor to heat up so much. You may also be able to lower the temperature at which the system throttles down the clock frequency to allow your system to run at even lower voltage. This will of course reduce performance in the cases where the clock frequency is throttled back… but depending on you use scenarios, you may not care about this.
The other feature available in CPUs is a turbo burst mode. Given that most laptops are running applications like Word, etc. that do not make heavy use of the processor, they typically do not heat the processor up too much. And therefore, when the CPU is cooler, it can run at a much higher clock frequency… but only for a short amount of time… i.e. until it heats up to the point where it can no longer run at that frequency. If your processor supports such a turbo boost mode, it may or may not work at the lower voltage you selected and you will probably want to run a test to determine if your processor’s turbo boost mode still works.
The advantage of undervolting your CPU is that you can extend the lifetime of your CPU… first by reducing the temperature that the processor runs at on average and thus the thermal cycling failure mechanisms. In addition you will reduce slight the hot electron injection into the gate electrode failure mechanisms which are reduced with lower voltage. However, processors usually last plenty long today… usually longer than the amount of time most people want to keep their computers before they are longing for a much faster and newer model so I am not sure this enhanced reliability is anything of value. And finally, it is worth noting that even though operating at lower voltage does somewhat reduce the maximum clock frequency, it does at the same time reduce the power dissipation and therefore also the operating temperature of the processor which tends to increase the maximum clock frequency… which depending on application usage, can somewhat balance each other out. And finally, the under voltage will reduce power consumption and thus enhance battery life, which maybe is your main reason for wanting to under volt your CPU in the first place.

回答很长很长，我将有用的信息提炼出来并翻译成人话：
1.降压对硬件完全安全无害，降压损坏cpu的说法是完全不存在的。
2.处理器制造的时候是将一堆处理器一起制造，造完后跑个分测试一下，发挥优秀的u贴上i7的标签，发挥平庸的贴上i5的标签，发挥差的次品就贴上i3（逃。。。。。。）
3.如何安全降压的方法（我在这里也讲过，传送门：http://tieba.baidu.com/p/5853076688）
4.关于温度墙，睿频的一些讨论
5.关于cpu老化缩缸的讨论：结论：降压反而会保护cpu，使其老化速度减慢
壹.降压会降温，降温可以减少”热循环失效机理“（ thermal cycling failure mechanisms）（我也不知道这是什么，似乎和电路焊接有关）
贰.降温可以减少”电极失效机理“（electrode failure mechanisms）（降温可以大大减少高速运动的热电子闯入cpu中的逻辑门电路的几率）
6.降压的优点与缺点：
pro：壹.降温，缓解笔记本电脑发热，使其能满血不撞温度墙运行很久（增强性能）
贰.节能，延长续航

con：壹.系统可能不稳定：直接断电重启，蓝屏，花屏死机
7.Paul Ledak认为：
壹.完全没有必要为了保护u而降压，毕竟一般u都能用十年以上，没到那时你就想换电脑了
贰.如果是为了提升续航与性能那到对于笔记本用户是一项不错的选择