English Community

Lenovo NotebooksLenovo Yoga Series Notebooks
All Forum Topics
Options

20 Posts

10-15-2019

FI

26 Signins

114 Page Views

  • Posts: 20
  • Registered: ‎10-15-2019
  • Location: FI
  • Views: 114
  • Message 51 of 143

Re: Yoga C940 4k - Fan runs constantly

2019-12-12, 21:08 PM

I tried Intel XTU a month ago but it said the CPU is unsupported. Then I tried ThrottleStop and was able to underclock to -80 mV. Going beoynd that made it unstable. With -80 mV idle temperatures were slightly smaller (maybe by 2-3 degrees) and the PC seemed to retain turbo clocks longer on load. I didn't feel big difference in how the fans kicked in, so I played safe and went back to the normal voltages.

 

What was surprising was that there was not much room for undervolting on my laptop. I've heard usually numbers like -110 mV or even -150 mV possible. Could of course be that my unit is one of the worse ones regarding undervolting, since it is always a gamble how good unit you get.

Reply
Options

10 Posts

12-02-2019

AU

14 Signins

75 Page Views

  • Posts: 10
  • Registered: ‎12-02-2019
  • Location: AU
  • Views: 75
  • Message 52 of 143

Re: Yoga C940 4k - Fan runs constantly

2019-12-13, 5:15 AM

I dont know how serious the question was, but for those interested, the fan noise is barely audible - at least under the workload I have put the C940 so far.  Not exactly the definitive answer, ask again in 6 months..

I havent heard coil whine on this one yet either, something I was trying to avoid by steering clear of the well known problem machines (XPS13 etc...), I havent put a stethoscope onto the keyboard yet though, so it may be there - just inaudible. 

Good to hear undervolting may be an option, though I would only be interested experimenting if the CPU temp/Fan operation became an annoyance, it isn't at the moment. 

 

BTW - Much of this talk is comparative, depends on the chipset quality, the motherboard build quality, how well the heatpipes/heatsinks have been pasted etc etc.   I'm not trying to sell them, only recounting my experience so far.  As I have been involved with IT equipment for most of my life, and have heard cpu and video card fans that sound more like an Airbus taking off,   comparatively, and for the performance level - these featherweight Lenovos C940s are excellent.   

 

....until they are not lol.

 

 

 

 

 

 

Reply
Options

8 Posts

12-19-2019

US

14 Signins

132 Page Views

  • Posts: 8
  • Registered: ‎12-19-2019
  • Location: US
  • Views: 132
  • Message 53 of 143

Re: Yoga C940 4k - Fan runs constantly

2019-12-19, 0:50 AM

I've been using mine for a few hours and the fans have literally turned off for less than 60 seconds a few times. It is a higher pitched fan noise that is a bit annoying. Tried the "cool & quiet" mode along with unplugging. Sitting next to my MacBook Pro 15" which is dead silent unless rendering video or something, it sounds like a jet engine just with chrome open with a single tab. Pretty unacceptable, imo. And re: battery life, it discharged 30% after an hour of web browsing with the brightness ~40%.

 

14" i7/16gb/4k version here.

Reply
Options

144 Posts

12-08-2019

US

183 Signins

1449 Page Views

  • Posts: 144
  • Registered: ‎12-08-2019
  • Location: US
  • Views: 1449
  • Message 54 of 143

Re: Yoga C940 4k - Fan runs constantly

2019-12-19, 1:48 AM

Can anyone here who has undervolted confirm if they have had a problem waking their lenovo c940's wake from sleep after undervolting? Have had two UHD 14 c940's in which if I undervolted at -80 it would cause the PC to not want to wake from sleep unless I hard restarted it. My only solution to that is reinstalling Windows directly from Microsoft's website and leaving the undervolt at about -50 to -60 volts. Any less and the bug starts occurring yet again. 

Reply
Options

21 Posts

12-24-2018

US

39 Signins

184 Page Views

  • Posts: 21
  • Registered: ‎12-24-2018
  • Location: US
  • Views: 184
  • Message 55 of 143

Re: Yoga C940 4k - Fan runs constantly

2019-12-24, 18:06 PM

Hi Guys, i got the maxed out C940 14 inch (4k 1tb SSD). And i love it.

Only one thing REALLY ANNOYS me, the high pitch of the fan noise. I have a yoga 920, which runs also often with the fan on, but it has a very low pitch sound that you can barely hear even at max speed, so it never bothered me, it sounds like a calm breeze/wind blow on the 920. However on the 940 it sounds like a mini jet taking off like a (piiiiiiIIIIIiiiIIiiiII), Even at low speeds the high pitch is noticeable and i can barely work on a silent room without noticing it.

Does anyone have any tips on how to make that high pitch sound go away? Is everyone having this high pitch or i got a defective unit?

I even thought about opening the laptop and putting some grease on the fan or something, but its a brand new laptop so i don't want to risk it.

Thank you!!

Reply
Options

32 Posts

07-03-2019

DE

65 Signins

483 Page Views

  • Posts: 32
  • Registered: ‎07-03-2019
  • Location: DE
  • Views: 483
  • Message 56 of 143

Re: Yoga C940 4k - Fan runs constantly

2019-12-24, 21:42 PM

Mine has the same high pitched sound, but I have mostly got used to it now. In a way it's reassuring that it appears to be normal and not a fault.

 

Unless this would be a case for a service replacement? :)

Reply
Options

42 Posts

12-18-2019

US

32 Signins

360 Page Views

  • Posts: 42
  • Registered: ‎12-18-2019
  • Location: US
  • Views: 360
  • Message 57 of 143

Re: Yoga C940 4k - Fan runs constantly

2019-12-24, 23:05 PM

 wrote:


Does anyone have any tips on how to make that high pitch sound go away? Is everyone having this high pitch or i got a defective unit?


My fans are also constantly running and it is becoming an 'almost deal breaker' for me, but it's not a "high pitched sound"

 

 


 wrote:



I even thought about opening the laptop and putting some grease on the fan or something, but its a brand new laptop so i don't want to risk it.

Thank you!!


I would definitely not recommend doing that...

Reply
Options

8 Posts

12-19-2019

US

14 Signins

132 Page Views

  • Posts: 8
  • Registered: ‎12-19-2019
  • Location: US
  • Views: 132
  • Message 58 of 143

Re: Yoga C940 4k - Fan runs constantly

2019-12-24, 23:36 PM

So one update that was suggested to me by Lenovo support is checking in the BIOS for the cooling mode (I forgot exactly what it's called). Mine was set by default on "extreme performance", when the default should be intelligent cooling. This option in the BIOS does seem different from what you get access to in the Vantage app (which seems to do absolutely nothing). Changing this option does seem to have made a difference but it's hard to tell.

 

One big thing that triggers the fans is having the charger plugged in. It seems like even being at 100% battery, having the charger plugged in generates a lot of heat, causing the fans to have basically 99% uptime, and then doing anything on the computer ramps up the fans even higher. While working unplugged, the fans only kick on occasionally, and is silent most of the time. However this isn't really an option since I only get ~4 hours of battery life, not enough to get through a whole work day.

Reply
Options

10 Posts

12-02-2019

AU

14 Signins

75 Page Views

  • Posts: 10
  • Registered: ‎12-02-2019
  • Location: AU
  • Views: 75
  • Message 59 of 143

Re: Yoga C940 4k - Fan runs constantly

2019-12-25, 3:15 AM

I agree with this - when the C940 is plugged in charging, the fans are definitely more constant.  Not 99% in my experience, more like 50-60% of the time, though that would depend on just how much charge the unit required, and what you are using it for while it is charging. 

The fans on this one are definitely not obtrusive either, just a faint whoosh, no jet engines... perhaps i was lucky.

 

It takes next to no time to charge the C940 though, and once charged I'm easily getting over 5 hours, so in my usage case I fully charge after using it, so I only occassionally require to have the laptop plugged in.  When its on battery, mine has rarely required the fans, the only time i can recall was during a major software download/install for WIN10 updates.

 

If I solely required a laptop for business purposes, which I don't - I have basic workhorses for that,  I would have gone with an Extreme 2 rather than the Yoga for numerous reasons - larger screen, dual SSDs, everything upgradeable/repairable, higher capacity battery and slightly better thermals.  Bit heavier but well worth it IMO, and to put that in perspective - 1.7-1.8KGs is still featherweight.   

 

So far, the C940 fits my requirement for a great travel convertible.   

 

 

Reply
Options

144 Posts

12-08-2019

US

183 Signins

1449 Page Views

  • Posts: 144
  • Registered: ‎12-08-2019
  • Location: US
  • Views: 1449
  • Message 60 of 143

Re: Yoga C940 4k - Fan runs constantly

2019-12-25, 4:00 AM
You must be one of the fortunate ones that can actually turn off the c940 and charge it for a whole hour to say it charges that fast for you. My charging rates are always garbo 3 hours since I need to be using it all day open :/

and if the fans bother anyone really just undervolt. Absolute 0% fans heard while undervolted at -57 mv and perfectly stable even for gaming.
Reply
Forum Home

Community Guidelines

Please review our Guidelines before posting.

Learn More

Check out current deals!

Go Shop
X

Save

X

Delete