12-02-2019 03:44 AM
Thats ironic, it was your brief youtube video I was watching yesterday, BTW thanks for posting that information. In your case, one problem will lead to the other, if the cores are idling at a consistently high temp then you will hear the fans spinning more often. Do you think that is a common issue or isolated - ie did you find many other C940 owners experiencing similarly high CPU idle temps?
The behaviour in your vid is complex to troubleshoot, since you need to dissassemble the laptop to check whether the thermal grease has been applied properly, the heatsink is properly aligned to the chip surface, then check the firmware is up to date, the actual CPU chip is not faulty, and the heatpipes and fans are exhausting hot air as intended. Beyond the firmware check I would not want to perform any other testing on a machine still under warranty, it would be back to base.
I can relate to your dislike of fan noise, if the UHD model is that bad - I will be returning it. I guess I will know whether this is a design issue very shortly, or its just affecting a few machines.
12-11-2019 09:31 PM
Same here, I have the fhd 14'' and the fans run every 2 min or so when it's plugged in. It doesn't run that often if you put it in cool/silence mode when it is not plugged in.
12-11-2019 09:39 PM - edited 12-11-2019 09:41 PM
I have used three yoga (C930, X1Y3, Yoga 940). I observed that even you don't do intensive things, plugging the laptop to the wall outlet leads to noisy fans at least when the battery level is below, say 75%. If you unplug it, no nosy fan. Is this normal and common among the Yoga lineup?
12-12-2019 03:48 AM
I have owned a C940 for a week now, the config is 16GB/512GB/i7 and UHD screen. I'm more than happy with it so far.
From my experience to this point - the fans are only coming on when its on charge, not constantly or even that noisy, they are only just audible. While it is unplugged, only using a web browser, I have yet to hear the fans at all. I am very noise sensitive, this laptop is not showing any noise issues up to this point.
On battery, the base is barely warm, while on charge.. and performing major Windows updates, its obviously getting a little warmer. I suspect the charge rate is quite high, given how quickly it achieves a full charge... hence the heat.
So far so good, I'm very happy with it, battery is still TBC, ~3 hours with 50+% remaining before recharging it, whether thats a *real* 6 hours is yet to be tested, its estimates were swinging quite a bit, at one point saying 13hrs left!
I usually have the screen on minimum brightness, highest setting is retina burning, I find low brightness is more than enough.
Will reserve judgement until i have loaded it up with a few more apps, looking good at the moment.
12-12-2019 03:58 AM
One thing I have noticed, which has been mentioned by other posters, is that the CPU does idle a little high. I havent seen any of the cores drop below the low 40 degree mark, though its questionable whethere this is a real issue, as I notice the peak temps for basic use remain quite low. I'd probably be happier if I could get it idling around 36-37.
I will check for firmware updates when i eventually get some time.
12-12-2019 04:14 AM
It's good to hear that your experience with the laptop has been good.
I have ordered a new top-end C940 14" after I experienced some coil whine with my first laptop. Should receive it today.
I have had both the UHD and the FHD model, and the temps are almost the same - around 45 degrees. The FHD feels slightly cooler to the touch on the outer chassis, but overall it was a negligible difference.
Has anyone tried undervolting the CPU? I've been contemplating doing it for my C940 because of the potential for lower temps, less heat, less chance for the fans to turn on, and even longer battery. Notebookcheck discovered some huge advantages on other Lenovo computers through undervolting. https://www.notebookcheck.net/More-performance-and-quieter-fans-with-Intel-XTU-Undervolting-the-Thin...
I don't have the technical know-how to do it, even though it seems simple enough. Does someone have any input on this?