thinkpad 480s i5-8250U hangs on load

[apple]

I have a t480s with i5-8250U. The defaults run fine for daily use, but when I watch a movie, game, streaming after about 20 minutes everything hangs like crazy. I'm assuming it's throttling on something since it takes about a minute to calm down afterwards. I have an external monitor so going full screen, so not sure if that could be an issue.

Has anyone else seen similar and if so, any ideas on how to confirm and/or recommend throttle changes?

Thank you!

 

[unclewebb]

Post screenshots or a log file that show what your CPU is doing when it is throttling. Hard to help you when I cannot see any of your settings.

Lenovo laptops have several unique bugs / throttling methods. ThrottleStop can be used to fix most Lenovo issues. Show me the main window, the FIVR, TPL and Options windows.

 

[apple]

Thank you unclewebb,

I had the logs running and was able to watch an entire ball game last night with no hangs. So I turned off logging. :-(

Then today it crushed to a slow after using zoom for 30 minutes. The logs were off but I turned them on as fast as I could so the beginning of the log file is when it's hanging. By hanging, I mean that every window is very slow, audio garbles, can't really navigate or switch windows, just very very sluggish to the point of almost unusable. I can eventually close chrome and other programs because I really don't know what else to do. After a few minutes, it came back. But the CPU is not pegged, memory is only 50%.

Attached are the logs (11-06) starting about mid-way through my hang event. It's funny because the logs show TEMP and PL1 throttling when the temp is low. It's like the throttling stayed even when the system cooled off. I don't know how this is supposed to work but that does seem strange.

Last night during the streaming game, I did see throttling but the video did not hang, worked fine, just my cpu freq went down as expected, but things still worked. In case you are curious, the 11-6 logs are attached. Everything worked like a champ on this one.

Screen shots of main/options/tpl/fivr attached. This should be default lenovo since I haven't changed anything yet. I had hwinfo running last night and the cpu freq went down when throttling as expected, but things did not hang or anything. Besides a fan noise and high cpu, all was great.

Thank you in advance!

 

[unclewebb]

Your 2023-11-07 log file shows that your laptop is thermal throttling at only 65°C. This turns your laptop into a 400 MHz slug even though the CPU temperature is barely warm. The engineers at Lenovo that dreamed up this feature are idiots. No worries. ThrottleStop has a feature that was specifically written to fix this problem.

Open the ThrottleStop Options window, on the right side check the PROCHOT Offset box, leave this set to 3, check the Lock PROCHOT Offset box, press OK to exit and save this setting.

In the TPL window check the MMIO Lock box which is near the top right. This will eliminate the MMIO PL1 15W power limit. Clear the Disable Controls check box. If you ever need to fine tune the power limits, now you can adjust the values in the Power Limit Controls section. Your cooling is only good for about 35W so I would change PL1 from 44W to 35W. You can leave PL2 at 44W. If your CPU gets hotter than you like, reduce the turbo time limit to 8 seconds or less. Consider changing PL1 to 30W or do both.

Clear the Lock check box for Power Limit 4. Press OK and reboot. When you open the TPL window, is there still a yellow lock icon to the left of where it says Power Limit 4? If you see that this is locked, leave it alone. If it is no longer locked, change Power Limit 4 from a value of 71 to a value of 0. Press Apply and you should see both boxes on this line showing 0. The right box is where you enter Power Limit 4 request values and the left box shows what value the CPU is currently using.

In the FIVR window check the Unlock Adjustable Voltage box for both the core and the cache and set IccMax to the max, 255.75.

Run another log file with these updated settings. Post another round of updated screenshots if you need me to double check the changes you made to your settings. An 8250U running at 3400 MHz will result in a night and day different user experience compared to when this CPU is being throttled to 400 MHz. A 750% increase in performance by checking one box in ThrottleStop. That is amazing. The Lenovo engineering team needs to give their heads a shake. Hopefully nothing falls out.

If your computer runs reliably with these settings, then you can undervolt your CPU if you want to reduce heat. Most similar CPUs are 100% stable with the core and cache offset voltages set to somewhere around -50 mV to -70 mV. Enter these values into the FIVR window. Run the TS Bench 960M test for a minute or two after making any voltage changes. You can stop this test at any time. If the TS Bench reports any errors or if your computer crashes while playing a game or doing any other stress test, that means your undervolt settings are not stable. Your CPU needs more voltage if this happens.

Edit - Your 2023-11-06 log file shows that you need to improve cooling. Have you ever cleaned out your laptop and blown out the dust? The heatsinks that Lenovo uses are OK for a 15W CPU but struggle when trying to run an 8250U at full power.

 

[apple]

Thank you very much, I'll give all that a try. But any idea why it was throttling today at 65 but yesterday did not start throttling until 97? In yesterday's logs it DID do the right thing bouncing on/off at 97. But today, it got "stuck" and didn't stop throttling.

But it clearly does not do that all of the time. In fact, most of the time and on all benchmarks I see it turning off throttle when it dips below 97. Just not on today's soom call. Are you saying that was a design to be *sometimes* throttling at low temps? It does seem random since most of the time it goes up/down and throttling really repsect the 97 degree max. I can't replicate that at all with any tests, it's random to me.

And yes, I probably need to clean it again, that's a great idea. It's always running hot and in the docking station most of the time. I've opened and cleaned it before so will do again. I don't trust myself to re-apply the heat sink so it's still original from 5 years ago.

I'll test out the settings again. This throttling at low temps is random so I'll have to leave it for a while to test but will report back in case anyone else finds this thread.

Thank you so much!

 

[unclewebb]

throttling at low temps is random

If you followed my advice and checked the Lock PROCHOT Offset box in the Options window, this problem is fixed. No need to test anything. This feature prevents the throttling at low temperature problem from happening.

You will have to ask the clown at Lenovo that engineered this feature to try and find out why it happens. As soon as I see this problem, I immediately know that the person I am helping has a Lenovo laptop. They are the only company that is randomly changing the thermal throttling temperature to the low and absurd temperature of 65°C.

re-apply the heat sink so it's still original from 5 years ago

Surprisingly, some thermal pastes are still working well after 5 years. It might still be OK. That is why I recommend first blowing the dust out and seeing where you are at. Some new and popular thermal pastes are only lasting 5 days on mobile CPUs. Changing out something that is still working OK might not be worth it.

 

[apple]

Everything continues to work great, thank you for your help!

 

[apple]

Hi Unclewebb,

I just upgraded to a new lenovo T14s. It has this as CPU:

Processor Intel(R) Core(TM) Ultra 5 135U, 1600 Mhz, 12 Core(s), 14 Logical Processor(s)

Unless throttlestop when first installed changes anything, it looks like they fixed the default temp throttling. The attached logs show the temp must be pretty high.

But it looks like PL1 is again set to 15. Do we think that can or should be increased like on the 480?

Thank you!

 

[unclewebb]

Some Lenovo laptops use their control software to randomly vary the thermal throttling temperature. I would always check the PROCHOT Offset box and the Lock PROCHOT Offset box to prevent this from happening.

Intel has increased the thermal throttling temperature up to 110°C for these new Core Ultra CPUs. The 5°C PROCHOT Offset value brings the thermal throttling temperature down to 105°C instead of the Intel recommended 110°C value.

Intel® Core™ Ultra 5 Processor 135U (12M Cache, up to 4.40 GHz) Product Specifications

Intel® Core™ Ultra 5 Processor 135U (12M Cache, up to 4.40 GHz) quick reference guide including specifications, features, pricing, compatibility, design documentation, ordering codes, spec codes and more.

ark.intel.com

I would also always check the MMIO Lock box to get rid of the 13 Watt MMIO PL1 power limit and the 35W MMIO PL2 power limit. HWiNFO calls the MMIO turbo power limits the Dynamic power limits because they can be changed at any time. Best to lock out the MMIO limits and then you can clear the Disable Controls box and set the MSR PL1 and PL2 power limits however you like. Setting MSR PL1 to 30W and MSR PL2 to 35W looks about right.

 

[FreedomEclipse]

I dont wish to derail the thread here. But if you love the T480 but live in a hot climate. This cooler mod might help you a fair bit.

Its fairly simple mod that requires barely any technical know how to do and will drop your temps quite considerably if you follow his instructions. As for his choice of thermal paste I would recommend SYY 157 over his kryonaut as its more resistant to pump out so should last longer without the need to reapply it.

If you are more technically advanced, you can use PTM7950 or Thermalright Heilos - which has now been established as 'S' tier among regular cooling pastes. Its really good stuff but it can take some fiddling to get it on but its the best thermal interface you can buy.

 

[eidairaman1]

I dont wish to derail the thread here. But if you love the T480 but live in a hot climate. This cooler mod might help you a fair bit.

Its fairly simple mod that requires barely any technical know how to do and will drop your temps quite considerably if you follow his instructions. As for his choice of thermal paste I would recommend SYY 157 over his kryonaut as its more resistant to pump out so should last longer without the need to reapply it.

If you are more technically advanced, you can use PTM7950 or Thermalright Heilos - which has now been established as 'S' tier among regular cooling pastes. Its really good stuff but it can take some fiddling to get it on but its the best thermal interface you can buy.

Otherwise the 2 cooling pads i provided in other threads might be a solution as well...

 

[FreedomEclipse]

Otherwise the 2 cooling pads i provided in other threads might be a solution as well...

There are no such things as half measures on TPU


Also an internal cooling mod trumps being constantly tethered to a cooling pad. Its an extremely simple straightforward mod that doesnt require a lot of technical skill or know how to do