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The original was posted on /r/pcmasterrace by /u/EdLovecraft on 2024-11-14 13:24:21+00:00.
To clarify in advance, I am Chinese, and most of this post was translated into English by AI.
TD;DR: All HX series i9 mobile processors exhibit a peculiar PL4 power limit bug. Whenever there’s a frequency fluctuation, throttling is triggered without apparent reason, regardless of the actual power consumption. This means that your processor will never be able to run at its maximum performance due to this dumb issue during gameplay. It appears that Intel has been aware of this problem for some time but has been reluctant to address it.
Detail:
In February, I purchased the MSI Vector 16 HX A13VHG gaming laptop and soon noticed an unusual issue: the CPU frequently triggered Electrical Design Point/Other (EDP Other) throttling, even during idle. Based on my experience and online resources, I suspected that current limits were causing this. I accessed the BIOS and set both TDC and Icc Max to their maximum values, but the throttling persisted. I then theorized that MSI’s Embedded Controller (EC) might be enforcing these limits, rendering BIOS adjustments ineffective.
Given MSI’s reputation for high customizability, I sought assistance on MSI’s official forums and Chinese platforms like Tieba (similar to Reddit) but received no responses. Frustrated, I began vocally criticizing MSI on these platforms.(I know I sound like an asshole) This drew significant attention, and many Chinese users became aware of the frequent throttling issues with MSI laptops. In May, Zhang Hongguo(张洪国) from Beijing Shengyuan Liyue Technology Co., Ltd.(北京圣元利业科技有限公司), an MSI retailer, reached out to me. He expressed interest in collaborating with me and MSI’s Taiwan headquarters to test solutions for the throttling problem.
Mr. Zhang suggested that I try disabling DTT (Dynamic Tuning Technology) to see if it could resolve the throttling issue and here’s the conversation:
Me: Disabling DTT still resulted in frequent throttling.
Zhang: Alright, got it. Please send me the specific impacts or symptoms you’re experiencing during gameplay, and I’ll report them to the Taipei headquarters. I’ll update you as soon as I have any news.
On May 10th, Mr. Zhang told me, “We’ve roughly figured out where the problem lies—it’s related to the PL4 value.” I also conducted some research, and indeed, one of the potential triggers for EDP Other is the PL4 value. Therefore, the frequent throttling occurs because the power consumption frequently reaches the PL4 threshold.
After several days of waiting, Mr. Zhang finally sent me a BIOS update that “resolved” the throttling issue. This BIOS increased PL4 from 240W to 330W. After flashing the BIOS, I no longer experienced frequent throttling during idle periods. However, I noticed that when playing games, the throttling still occurred just as frequently as before. So, I continued sending Mr. Zhang various data to help them identify the root cause of the problem.
A month later, during which I kept asking him in hopes of finding a complete solution to the throttling issue, Mr. Zhang finally explained to me on June 20th why the PL4 power limit throttling occurred so frequently and why they couldn’t resolve it. Here’s the conversation:
Me: Is it possible to completely fix the frequent throttling that still occurs during gaming?
Zhang: There isn’t a good solution for this. Throttling during gaming is mainly caused by Intel’s PPP estimation values. Unless PL4 is forcibly set to over 400W, the throttling will still occur. We’ve tested it, and even setting PL4 to 370W or 380W still triggers throttling.
Zhang: Before discussing PL4, it’s important to understand the concept of Potential Peak Power (PPP). This power value is Intel’s theoretical estimate of the maximum possible power consumption. Since it’s an estimate, it doesn’t represent the actual power consumption, but rather a prediction of what the instantaneous power consumption of the system might be at a given moment. PL4 is used to limit the PPP value. When the estimated PPP exceeds the PL4 value, the system will trottle the CPU to prevent “overload.”
Zhang: With a 330W adapter and the battery together, the maximum power provided is still less than 400W.
Zhang: When the CPU starts to turbo(increase the frequency), Intel CPU will estimates the PPP value.
Zhang: When the estimated PPP exceeds 330W, throttling will be triggered.
Me: It does feel similar to the recent bug with Intel’s desktop eTVB algorithm. If the mobile PPP estimation is behaving like this, it could indeed be considered a bug as well. It seems like Intel is facing a lot of issues lately, and this problem with throttling is just another example of that.
Zhang: Yeah, the actual real power consumption isn’t enough to trigger throttling. The discrepancy between the PPP estimation and the actual power consumption is just too large, which causes unnecessary throttling.
Zhang: In gaming, as long as the CPU engages in turbo mode(increasing CPU frequency), PPP takes the highest priority, as it is used to prevent overload.
Zhang: After that, PL1, PL2, or temperature throttling is used to limit the frequency.
Zhang: Let’s wait and see if the next microcode update can fix this issue.
Zhang: I suspect that during gaming, when the frequency of a single core rises, the algorithm might incorrectly predict that all cores will increase in frequency, leading to an overestimation of the PPP.
Zhang: I’ve heard from 火鸡（蒸気火鸡, a famous Chinese tech video creator) that Intel is aware of this issue, but whether they will fix it is still uncertain. This problem seems to be more noticeable on the Ultra series.
This throttling issue exists across all HX series i9 processors. I’ve searched and asked around on various Chinese social media platforms, and everyone who has tested it experiences the same problem. If you also have an HX series i9 processor, you can test it as well. I believe you’ll encounter the same issue.
Before Intel fixes this issue, I wouldn’t recommend any gaming enthusiasts to buy Intel gaming laptops, because you won’t be able to fully enjoy the performance you paid for. Your performance will always be limited by this stupid issue.