Screen Tearing and PWM?
Screen Tearing and PWM?
- Does the Steam Deck use PWM for the screen? Does the screen flicker?
- While gaming, is there some kind of screen tearing or is there some kind of VRR/Freesync being used? Otherwise, what settings do you use to avoid screen tearing (FPS locking, etc.)?
Thanks!
Not familiar with PWM. I know it's some anti-flicker tech, but nothing else. I've never noticed flicker on Steam Deck's screen [edit: but I'm not very sensitive to it].
Steam Deck does have an adjustable refresh rate screen which can be set to any refresh rate between 40 and 60 Hz. It does not support VRR (real time adjustment), but usually you play around to get best FPS you can, then you lock the refresh rate to the same frequency (unless your FPS is below 30, then you lock it to twice the rate).
However, if you connect the Steam Deck to an external screen that does support VRR, Steam Deck is compatible and will work. Just not with the inbuilt screen.Steam Deck has VSync on by default to prevent tearing, and it's applied on top, to all games. You can optionally disable VSync by toggling the 'Allow Tearing' option in the quick menu.
PWM = Pulse Width Modulation, a way of changing the power of a signal to 'emulate' a different voltage or amperage by rapidly varying the 'width' of the signal, at a high enough frequency that you shouldn't notice it.
Basically, it 'stutters' the signal. That's all well and good until it starts to get into the frequency that users are sensitive to (Which is different for everyone). At that point it can cause headaches, nausea, eye strain, migraines and possibly even increasing any epileptic effects.
The other issue is normally it's fine, but maybe when the brightness is down really low, you might get a 120Hz 'flicker' sort of like an old Flourescent light fixture, as it turns off and on the LED backlighting slow enough that you start to actually experience it. For me, I've not noticed it even at very low brightnesses and dark rooms, but I'm not sensitive to it at all.
Yes it flickers, more noticeable when setting lower frequencies, it personally doesn't bothers me at all, but I never had that problem with other devices neither. I think some people couldn't handle it. Ad of course apart from personal sensitivity there is always the brightness and illumination of the place you are that would affect how visible it is
About the tearing, first of all due the screen being a vertical one any tearing would be vertical. Then if using SteamOS due to using Wayland until recently it was impossible as that forced always VSync. But now there is a new option to allow tearing, I haven't test it. There isn't VRR, well for the device screen, I think VRR worked for monitors supporting it connected to it but not 100% sure.
Thanks. Does it also flicker at 100% brightness?
So, vsync should eliminate screen tearing m, at the cost of performance (lower fps when enabled)?
Vsync synchronizes the framerate with the refresh rate, no matter how fast your GPU can render them. The GPU can typically render the frames much faster than the 60 FPS that the screen allows, so instead of loading a frame that just happened, your screen may be loading a frame that happened 1/60th of a second ago. The advantage is that the screen always receives a full frame so you don't get any tearing. The downside is that your inputs may appear delayed by a frame or two.
I do not know for me is not noticeable...but maybe is there and I do not see it.
And the VSync the most annoying thing usually is that well, it adds input lag. Lower fps I do not think so.... I mean of course it will be capped to the screen frequency, so 60 max.
The Deck uses PWM. I'm one of those unfortunate few that ends up feeling nauseous when using 40Hz. I don't notice the flickering directly, but 10 minutes of gaming or so and my head is spinning. I don't get the same issue at 45Hz or higher.
Good to know. Thank you! Does it change with brightness?