12-23-2017 12:06 AM
I have recently bought a Yoga 520 with an Intel Core i5-8250U and Geforce 940MX and so far I have been impressed with it except for one thing : Under a short, full load, the CPU throttles really, really bad. It would start strong and around 2.6-3.4Ghz but then around 2-3 minutes later it would stay at 1.6Ghz. Once it hits 1.6Ghz, it won't clock any higher even if the temperature/load has been back to normal unless i reboot it. I have tried to update the BIOS and even relpacing the thermal paste with a high-performance one and it still throttles.
My question is, is this normal? I see no reason for throttling the CPU since the thermal headroom is still plenty when its under load (around 66 degrees celcius). Or perhaps does Lenovo implemented a specific power management? such as setting the CPU cTDP-down to 10W-12W instead of the normal 15W? My reasoning for this is that the HWmonitor reading for the CPU power never really exceeds 11 Watts once it's under full load.
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12-27-2017 09:06 AM
Well this is disheartening. I've been waiting for four days and not a single reply. I was hoping for a confirmation from the Lenovo staff or at least fellow Yoga 520 user who have the same problem. No matter, I have found the solution by myself. I think it is probably related to lenovo's own clock profile in which a when the processor hits 100% utilization, no matter how momentary, it would downclock to 1.6Ghz almost immediately and not boosting any higher until the temperature drops to a certain degree even if the temperature and power clearly allows for a much higher clockspeed. So I found a way to restore the 'normal' i5-8250U behavior by running an app called ThrottleStop. No tweaks whatsoever, just run it and the i5-8250U will behave like an i5-8250U should, clocking at 2.8-3.4Ghz the first few minutes and stays at 2.2-2.3Ghz under sustained loads. The temperature does noticeably increase at 70 degrees C average under 100% load compared to 60 ish degrees C average at 1.6Ghz. That is still very much under the Tjunction of 100 degrees, though. So I'll bite the bullet, for the performance that I should have got from the get go.
01-02-2018 04:26 AM - edited 01-02-2018 04:34 AM
I have same problem. But I think i5 8250u on Lenovo Yoga 520 has disabled turbo boost.
I don't have a solution about this issue.
If use ThorttleStop Software, it will damage the cpu becouse of high temperature (70-99°C)
01-02-2018 05:22 AM - edited 01-02-2018 05:42 AM
It would seem that the cooling solution on the Yoga 520 is inadequate hence the 1.6ghz downclock. Yeah, mine does get really hot. Dangerously close to the 100 degrees threshold when the GPU and the CPU are moderately utilized (I have failed to account the GPU load on my first post about throttlestop as the solution).
I have yet again found the fix, though. You'll want to undervolt your CPU and enable intel Speedstep and set the value more towards power saving (around 145 and up to 225). I've got mine at around -100mV undervolt and Speedstep value set at 156. It is now occasionally boosting around 3.0-3.4Ghz under light load, 2.6-2.8Ghz under moderate load, and 2.2Ghz under full, sustained, load with highest recorded temperature of around 76-84 degrees C under full GPU load+moderate CPU load. Pretty comfortable I think. Do note that I have made another tweak though by replacing the thermal paste with a Noctua NT-H1. Hope this helps.
03-30-2018 10:01 PM
this is helpful and really helped get my flex 5 working much faster. However I would not really call this a fix. I had purchased an ASUS flipbook before getting this laptop and I love the build quality on this much better than the ASUS however it had no limitations except for temps when it came to its performance. If the laptop was plugged in I could get 3.4 ghz all day long at 100% usage as long as thermals were in check. I dont understand why this is locked down on Lenovo computers. Tj max on these processors is 90C why are we kept to 15 watts of usage when it is capable of boosting so much higher. Just give us a bios update that will allow us to choose what we want it to do. Is Lenovo not aware that this also hurts performance figures in reviews? I just dont understand the decision on this and why it was done.
04-09-2018 02:16 AM
I have the exactly same problem.
>> Install linux.. not working
>> Update BIOS,Chipset not working
>> Sent notebook a Guarantee.. they changed the fan and sent it back.. but not WORKING
I will not prefer the lenovo product again
04-09-2018 03:21 AM - edited 04-09-2018 03:22 AM
It's indeed a workaround using Throttlestop, but i'm really enjoying my laptop since installing it, just hope it stays like that.
You really get a lot of features for the money, the Yoga 520 is arguably the most feature rich laptop for the money, and laptops that are priced way higher sometimes suffer even worse throttling.
04-09-2018 05:47 AM - edited 04-09-2018 05:49 AM
As I have posted before, the reason that Lenovo is limiting the CPU frequency is likely due to the anemic cooling solution, at least when you account for simultaneous CPU and GPU load. I do agree that using ThrottleStop cannot really be called a fix, it's more akin to a band aid. It helps, but is a bit of a hassle. But what else can we do really when the cooling solution is not up to the task. I'll reiterate that the best thing we can do are:
As for me I'm not really that surprised with this design choice. I have had experience with an even worse laptop cooling solution from Lenovo. It was the Ideapad G405s and my god was it the worst. The fan vent was straight up sealed. Not filtered, but sealed shut with a thin sheet of plastic. The laptop would just shut down under certain load and the battery life was terrible. Just bad all around.
Seeing Lenovo does this kind of thing again kinda bummed me but well there's your fix. As for now, I'm perfectly fine with my current setup but yeah, they need to stop doing under-designed laptop cooling solutions.