According to oled-info.com, "Several studies claim that about 10% of people experience discomfort when viewing PWM displays (while the rest are either completely okay or with some very mild discomfort). Some people suffer very badly and the flickering may result in other health issues." PWM is supposed to be the main cause of flicker, but according to notebookcheck, “some devices do not use PWM at all, but still showed a measurable brightness flickering during our review (e. g. [from] poor shielding of the power adapter).” Dear notebookcheck: So how do you determine what the cause is? Notebookcheck continues: "The problem is that it’s a standard industry practice to use displays [i.e., panels] sourced from multiple manufacturers for the same laptop. So while the unit we test might be PWM free, the next one under the same model name might have PWM - while they should be identical on the specsheet, in reality, they are not...This is a problem impossible to solve for us. We at Notebookcheck cannot test every single Notebook on earth and its almost always impossible to tell how many different display panel variations there are for a product, because the manufacturers are mostly intransparent about this stuff...In the end, it’s the manufacturers who are not transparent about their products. It’s their task to make more honest spec-sheets and inform people about their products." Exactly. Look at how Lenovo's sales rep responded to me: Andersson Steve M.: Hello, thanks for contacting Lenovo Sales. My name is Andersson Steve M. (Rep ID: 2900729623). At the conclusion of this chat, there will be a brief, two-question survey, scoring from 1-10 where 10 is the best. Please be sure to ask about our flexible payment options! Me: I need c940 14" info. Andersson Steve M.: Welcome to Sales Chat Department. How can I assist you with your purchase today? Me: There are 5 displays available? Andersson Steve M.: Yes Me: Do any use pwm? Andersson Steve M.: all of them Me: Notebookcheck says the 1080p glossy does not. Andersson Steve M.: Well, that is the information I have about displays Me: I'm not even sure what it means. What does pwm mean? Andersson Steve M.: Pulse-width modulation Me: Is that good or bad? Andersson Steve M.: That is good because it improve the resolution and avoid you headache Me: Have a nice day! Note the level of English: ...it improve the resolution and avoid you headache! Also note that at the time of this conversation there were actually only 4 display options listed on Lenovo's website: 1080p and 3840p, with or without anti-glare. A couple of days later, that was changed to indicate that there are only 2 display options. The anti-glare options were removed. So to find out what panel your display has, you can do some detective work to make an educated guess before you buy, as I did here for the Lenovo C940-14iiL: 3840p 500-nit glossy HDR (supplier?) pwm = ? The 3840p 500-nit glossy HDR in the S940 is the AUO B140ZAN01.3, and it also has pwm = 0. After browsing through the list of Lenovo displays laptopmedia.com has made, I think that's the only 3840p 14" display Lenovo uses. Note, however, that laptopmedia measured it at 445 nits, while notebookcheck measured it at 536. Or you might put the HWiNFO utility on your flash drive and run it on a showroom computer at Best Buy or the like. That is the suggestion of laptopmedia.com for finding the part number of a panel. Or you could take the panel out and have a look. Or you could use your oscilloscope. Or do the pen-wave test or the like. Then return the thing if you don't like the results. Notebookcheck claims that PWM is a necessary evil: “New technology such as what is found in smartphones is too small and designed to use too little power to utilize any alternatives such as analog controllers.” Dear notebookcheck: Then why are there numerous smartphones listed on your website with PWM = 0? And you also say the Razer Blade 15 Studio Edition with OLED has PWM=0. Notebookcheck continues: “…manufacturers such as Xiaomi and OnePlus decided to offer DC dimming in their devices with AMOLED displays on a trial basis. We have already examined the effects of the new technology (called Flickering Protection by Xiaomi)…” Actually, Xiaomi's DC dimming is used in combination with PWM. Moreover, it seems to be doable with a firmware update.