6 ms·

I've had this random graphics stutter that would never ever show up in any benchmark at all, but weirder than anything else was that it also wouldn't show up in

I've had this random graphics stutter that would never ever show up in any benchmark at all, but weirder than anything else was that it also wouldn't show up in recordings made on that machine. To save you the story of weeks-long debugging efforts - the problem turned out to the monitor. It was a Dell Ultrasharp 25", and (as I now know) they all had an issue where the monitor would freeze roughly every 20 seconds for a frame, because the monitor was advertising the refresh rate to windows as 59.95Hz but it was actually refreshing at 60Hz internally - the timing would get out of sync pretty much exactly every 20 seconds, causing the monitor to "pause" and freeze - which looked like stutter when playing games. The solution was using some kind of program(forgot the name now) which basically overrode the refresh information being sent from the monitor and forced windows to refresh at exactly 60Hz and no less - then it worked fine. But of course if you used it with a PS4 then you didn't have any way to do that and just had to suffer this stutter every 20 seconds.

croutonwagon 4y ago
Similarly I have a monitor at home that, for whatever reason, will stutter on a game in fullscreen UNTIL i go and manually set its refresh rate. I have to flip it between 59.95Hz and 60 Hz in the windows advanced settings, changing that setting basically makes the monitor re-initialize and then everything is fine. It happens every time I wake the monitor from sleep (ie: my computer rarely, if ever goes to sleep, but the monitors will turn off after 10 minutes of inactivity) This only really happens with games. DirectX or Vulcan doesnt matter. Doesnt affect things like youtube, plex etc. But any game in fullscreen or borderless windows on that screen, i have to basically just change that setting back and forth to keep my sanity.
- danudey 4y ago
  This reminds me of a sound card I bought way back when (22 years ago or so); it was a wavetable-supporting, Soundblaster Pro-compatible card that I got on sale for 50% off without making any effort at all to look it up online or even check the kernel for Linux support. It worked and sounded great in Windows; it also worked and sounded great in Linux, with one exception: the card supported ISA PNP, which was great, but the kernel module for the sound card wouldn't load unless I did `cat /proc/isapnp` first. I had no idea why, and it took a few reboots and trial-and-error to narrow it down to this janky workaround, but it worked so I just configured modprobe to run `cat /proc/isapnp > /dev/null` before trying to load the module and I never had to worry about it again. Technology sure is weird sometimes.
  - theevilsharpie 4y ago
    Many years ago, I had an Athlon 64 workstation paired with some type of 3Ware SATA RAID controller (a 9650SE, I think). Every other boot, the BIOS would fail to initialize the controller, leaving the computer stuck at a "non-bootable device" error until I could manually reboot it. My solution? A perpetually plugged-in USB flash drive with a small boot loader that would simply reboot the machine again, set to a lower boot priority than the SATA RAID controller. It was pretty stupid, but if it's stupid and it works...
    - bombcar 4y ago
      I had something similar and just used the USB to hold ... LILO at the time? Can't recall.
  - goosedragons 4y ago
    My ThinkPad has something similar with the microSD card slot. You have to type "lspci" for it to notice there's an SD card inserted. I don't use the slot much so it's not a big deal but it's literally the only thing that doesn't play nice with Linux.
    - Arnavion 4y ago
      If there's a udev event generated when you insert the SD card, you could write a udev rule to exec `lspci` when it happens.
  - cwillu 4y ago
    I keep a hacks file in my home directory so that when a random thing breaks after an upgrade or a new system, I can quickly review the fixes that I needed three years ago but that upstream couldn't be bothered to fix. Open-source is the best worst-thing ever.
- Dwedit 4y ago
  How are you able to pick between 59.95Hz and 60Hz? From what I've seen in Windows, it is keeping track of refresh rates as big rational numbers with full precision, but then when it's time to actually switch to a video mode, everything gets rounded to an integer, and it just picks whatever mode is closest to that integer value. Would probably need to use Custom Resolution Utility to define a refresh rate that you really want.
  - croutonwagon 4y ago
    In windows its just right click on desktop>Display Settings>scroll to bottom>Advanced Display Settings Then select your monitor in the drop down and the refresh rate. Which is negotiated by the monitor and the video card. I suppose unplugging and pluggin the cable back in may help. But ive changed cables, bought new ones, tried adapters to change the type (ie: hdmi to DP etc). Its just something with the display. And Im too lazy to bend over and unplug/plug it in, so i just do the refresh rate trick.
itsboring 4y ago
Oh wow, that would drive me mad. That's one of those subtle human-machine interaction problems where sometimes people don't believe you (and maybe you start to doubt yourself even). And then people start throwing around studies saying humans don't perceive this or that under some millisecond threshold or whatever. Before high refresh rate screens, I was one of those people that would turn off v-sync in games because the additional input lag bugged me just enough, JUST on the edge of perception. I wasn't even a competitive player or particularly good, but it felt....mushy. Similar problem with playing old NES games on modern LEDs. For many years I had a mechanical keyboard I loved, but slowly and subtly over time the enter key would miss a keystroke. It was like 1 out of 300 times maybe, but it was just often enough for me to start doubting my own fingers. Finally couldn't take it anymore and just bought a new keyboard. Just goes to show that very subtle problems in a computer interfaces can have a big impact.
- beebeepka 4y ago
  We've had high refresh LCD monitors for well over a decade now and vsync is still the very first thing I disable. Lag is lag, high refresh or not
lawstorant 4y ago
Mate, Dell U2518D. I still have it and had the same span of feeling that something is off. I managed to capture it with a high-speed camera and it's even funnier than just a stutter. It produces VERTICAL tearing every 20 seconds. Nobody would belive me something like that is even possible. I wouldn't belive me if I didn't see it with my own eyes. Dell actually made a firmware verison that address it and people reported that it indeed fixed it. But guess what? You cannot download it! The only way to get newer FW was to buy a monitor from a newer production batch.
- gambiting 4y ago
  Yep, that's exactly it! It makes me very happy to know that I wasn't the only one to notice it(and it definitely felt like I was going mad for a while- seeing stutter where literally no tool could detect it). I found a forum thread on Dell's forums about it ages ago, I remember people sharing the refresh rate override fix, but I wasn't aware that Dell did eventually "fix" it in a later batch of monitor. That monitor did actually die for me literally 2 months ago(and just few months out of warranty, typical) but I was very glad to replace it with something else.
- ziml77 4y ago
  I found out that Dell doesn't make the firmware user upgradeable when I checked for any for my AW3420DW. The annoyance I'm trying to fix is minor enough that I decided it's not worth RMAing it to hope I get one that is both in good condition and has the new firmware. I'll have to be pretty desperate to buy a monitor from Dell again though.
- wlesieutre 4y ago
  I had the same sort of firmware issue with a Dell UP2414Q which was released in 2013. Major problems like half the screen not working or no picture at all. No you can't have the firmware update. You can exchange it for a refurbished monitor and "should" get the new firmware. There's a 53 page Dell forum thread about that disaster of a monitor: https://www.dell.com/community/Monitors/UP3214Q-UP2414Q-1-2-screen-issue-and-or-No-picture-after/td-p/4260496/page/53 https://www.dell.com/community/Monitors/UP3214Q-UP2414Q-1-2-... Amazing that nearly 10 years later they still can't update monitor firmware in the field.
deleted 4y ago
[deleted]
russdill 4y ago
I'm really struggling to understand why a monitor would be designed this way. It's already receiving a pixel clock and all the pixels, horizontal fields, and entire frames at 59.95Hz. There's absolutely no need for the monitor to be keeping track of a separate 60Hz clock anywhere. All I can figure is that it might have some motion blur or other interpolation feature and it's holding frames back after receiving them and displaying them from an internal buffer at 60Hz. In this case, you'll get occasional (but rare) tearing/stuttering no matter what since the computer's clock and the LCDs hypothetical clock are not syncronized.
- gambiting 4y ago
  So I'm only guessing, but I think it's because the internal display driver was actually working at 60Hz, but the monitor was just advertising the refresh speed incorrectly to any connected device as 59.95Hz. The error would accumulate and after about 20 seconds the monitor had to "stop" and resynchronize the clock.
- londons_explore 4y ago
  It's kinda hard to design hardware driven by someone else's clock. The easy and lazy solution is to generate your own clock signal at the rate you want, and then to buffer the data from their closeish-clock to your own. Obviously this has the downside of an extra frames latency and the occasional dropped frame when the clocks drift.
  - russdill 4y ago
    An LCD monitor that buffers frames? That would be really bad. The typically HDMI receiver chip does the lazy thing. Which is simply to receive pixels on one end, and transmit them out the other at the same rate that it receives them at. No buffering. https://www.analog.com/en/products/adv7613.html https://www.analog.com/en/products/adv7613.html
    - londons_explore 4y ago
      Typically monitors buffer frames because the LCD matrix itself has a maximum and minimum refresh rate - and the user may provide an input signal outside that rate. Even so, the anti-ghosting compensation algorithms typically only work at one rate.
flyinghamster 4y ago
Now that sounds a lot like a video version of an audio issue that I have with my Android phone and a BluStream hands-free kit. When playing music from any source, there will be skips at long, random intervals. I could back up the song, play the suspect phrase over, and it would be perfect. It's almost like there's some sort of subtle clock mismatch somewhere that eventually can't be papered over. I've had it happen on more than one phone, and I'd also note that my Sony headphones don't skip.
jiggunjer 4y ago
This reminds me of a weird phenomenon in my parents living room: Our Samsung TV would stutter and colors would distort when lighting the candles with a lighter (one of those long-neck trigger models). Never figured out why but I suspect an EM pulse was created with each trigger "click", which affected the cable signal.
- sitzkrieg 4y ago
  those piezo sparkers definitely can cause some decent em pulses like any sparks really
  - buescher 4y ago
    Yup. The poor man’s ESD gun.
garaetjjte 4y ago
>But of course if you used it with a PS4 then you didn't have any way to do that and just had to suffer this stutter every 20 seconds. You could splice cable DDC lines to I²C EEPROM programmed with patched EDID data.
- sebastien_b 4y ago
  Brilliant solution, but I would’ve dumped the defective-by-design monitor at that stage.
- lreeves 4y ago
  You can get EDID spoofers on Amazon for about 20$ for these kinds of issues.
d2wa 4y ago
(I’m the author.) I’ve tested with a different GPU and screen. The article focuses on the factors that made a positive impact on the problem. I’ve also swapped cables, disks, PSU, and other components.

croutonwagon 4y ago

Similarly I have a monitor at home that, for whatever reason, will stutter on a game in fullscreen UNTIL i go and manually set its refresh rate. I have to flip it between 59.95Hz and 60 Hz in the windows advanced settings, changing that setting basically makes the monitor re-initialize and then everything is fine. It happens every time I wake the monitor from sleep (ie: my computer rarely, if ever goes to sleep, but the monitors will turn off after 10 minutes of inactivity) This only really happens with games. DirectX or Vulcan doesnt matter. Doesnt affect things like youtube, plex etc. But any game in fullscreen or borderless windows on that screen, i have to basically just change that setting back and forth to keep my sanity.

danudey 4y ago
This reminds me of a sound card I bought way back when (22 years ago or so); it was a wavetable-supporting, Soundblaster Pro-compatible card that I got on sale for 50% off without making any effort at all to look it up online or even check the kernel for Linux support. It worked and sounded great in Windows; it also worked and sounded great in Linux, with one exception: the card supported ISA PNP, which was great, but the kernel module for the sound card wouldn't load unless I did `cat /proc/isapnp` first. I had no idea why, and it took a few reboots and trial-and-error to narrow it down to this janky workaround, but it worked so I just configured modprobe to run `cat /proc/isapnp > /dev/null` before trying to load the module and I never had to worry about it again. Technology sure is weird sometimes.
- theevilsharpie 4y ago
  Many years ago, I had an Athlon 64 workstation paired with some type of 3Ware SATA RAID controller (a 9650SE, I think). Every other boot, the BIOS would fail to initialize the controller, leaving the computer stuck at a "non-bootable device" error until I could manually reboot it. My solution? A perpetually plugged-in USB flash drive with a small boot loader that would simply reboot the machine again, set to a lower boot priority than the SATA RAID controller. It was pretty stupid, but if it's stupid and it works...
  - bombcar 4y ago
    I had something similar and just used the USB to hold ... LILO at the time? Can't recall.
- goosedragons 4y ago
  My ThinkPad has something similar with the microSD card slot. You have to type "lspci" for it to notice there's an SD card inserted. I don't use the slot much so it's not a big deal but it's literally the only thing that doesn't play nice with Linux.
  - Arnavion 4y ago
    If there's a udev event generated when you insert the SD card, you could write a udev rule to exec `lspci` when it happens.
- cwillu 4y ago
  I keep a hacks file in my home directory so that when a random thing breaks after an upgrade or a new system, I can quickly review the fixes that I needed three years ago but that upstream couldn't be bothered to fix. Open-source is the best worst-thing ever.
Dwedit 4y ago
How are you able to pick between 59.95Hz and 60Hz? From what I've seen in Windows, it is keeping track of refresh rates as big rational numbers with full precision, but then when it's time to actually switch to a video mode, everything gets rounded to an integer, and it just picks whatever mode is closest to that integer value. Would probably need to use Custom Resolution Utility to define a refresh rate that you really want.
- croutonwagon 4y ago
  In windows its just right click on desktop>Display Settings>scroll to bottom>Advanced Display Settings Then select your monitor in the drop down and the refresh rate. Which is negotiated by the monitor and the video card. I suppose unplugging and pluggin the cable back in may help. But ive changed cables, bought new ones, tried adapters to change the type (ie: hdmi to DP etc). Its just something with the display. And Im too lazy to bend over and unplug/plug it in, so i just do the refresh rate trick.

itsboring 4y ago

Oh wow, that would drive me mad. That's one of those subtle human-machine interaction problems where sometimes people don't believe you (and maybe you start to doubt yourself even). And then people start throwing around studies saying humans don't perceive this or that under some millisecond threshold or whatever. Before high refresh rate screens, I was one of those people that would turn off v-sync in games because the additional input lag bugged me just enough, JUST on the edge of perception. I wasn't even a competitive player or particularly good, but it felt....mushy. Similar problem with playing old NES games on modern LEDs. For many years I had a mechanical keyboard I loved, but slowly and subtly over time the enter key would miss a keystroke. It was like 1 out of 300 times maybe, but it was just often enough for me to start doubting my own fingers. Finally couldn't take it anymore and just bought a new keyboard. Just goes to show that very subtle problems in a computer interfaces can have a big impact.

beebeepka 4y ago
We've had high refresh LCD monitors for well over a decade now and vsync is still the very first thing I disable. Lag is lag, high refresh or not

lawstorant 4y ago

Mate, Dell U2518D. I still have it and had the same span of feeling that something is off. I managed to capture it with a high-speed camera and it's even funnier than just a stutter. It produces VERTICAL tearing every 20 seconds. Nobody would belive me something like that is even possible. I wouldn't belive me if I didn't see it with my own eyes. Dell actually made a firmware verison that address it and people reported that it indeed fixed it. But guess what? You cannot download it! The only way to get newer FW was to buy a monitor from a newer production batch.

gambiting 4y ago
Yep, that's exactly it! It makes me very happy to know that I wasn't the only one to notice it(and it definitely felt like I was going mad for a while- seeing stutter where literally no tool could detect it). I found a forum thread on Dell's forums about it ages ago, I remember people sharing the refresh rate override fix, but I wasn't aware that Dell did eventually "fix" it in a later batch of monitor. That monitor did actually die for me literally 2 months ago(and just few months out of warranty, typical) but I was very glad to replace it with something else.
ziml77 4y ago
I found out that Dell doesn't make the firmware user upgradeable when I checked for any for my AW3420DW. The annoyance I'm trying to fix is minor enough that I decided it's not worth RMAing it to hope I get one that is both in good condition and has the new firmware. I'll have to be pretty desperate to buy a monitor from Dell again though.
wlesieutre 4y ago
I had the same sort of firmware issue with a Dell UP2414Q which was released in 2013. Major problems like half the screen not working or no picture at all. No you can't have the firmware update. You can exchange it for a refurbished monitor and "should" get the new firmware. There's a 53 page Dell forum thread about that disaster of a monitor: https://www.dell.com/community/Monitors/UP3214Q-UP2414Q-1-2-screen-issue-and-or-No-picture-after/td-p/4260496/page/53 https://www.dell.com/community/Monitors/UP3214Q-UP2414Q-1-2-... Amazing that nearly 10 years later they still can't update monitor firmware in the field.

deleted 4y ago

[deleted]

russdill 4y ago

I'm really struggling to understand why a monitor would be designed this way. It's already receiving a pixel clock and all the pixels, horizontal fields, and entire frames at 59.95Hz. There's absolutely no need for the monitor to be keeping track of a separate 60Hz clock anywhere. All I can figure is that it might have some motion blur or other interpolation feature and it's holding frames back after receiving them and displaying them from an internal buffer at 60Hz. In this case, you'll get occasional (but rare) tearing/stuttering no matter what since the computer's clock and the LCDs hypothetical clock are not syncronized.

gambiting 4y ago
So I'm only guessing, but I think it's because the internal display driver was actually working at 60Hz, but the monitor was just advertising the refresh speed incorrectly to any connected device as 59.95Hz. The error would accumulate and after about 20 seconds the monitor had to "stop" and resynchronize the clock.
londons_explore 4y ago
It's kinda hard to design hardware driven by someone else's clock. The easy and lazy solution is to generate your own clock signal at the rate you want, and then to buffer the data from their closeish-clock to your own. Obviously this has the downside of an extra frames latency and the occasional dropped frame when the clocks drift.
- russdill 4y ago
  An LCD monitor that buffers frames? That would be really bad. The typically HDMI receiver chip does the lazy thing. Which is simply to receive pixels on one end, and transmit them out the other at the same rate that it receives them at. No buffering. https://www.analog.com/en/products/adv7613.html https://www.analog.com/en/products/adv7613.html
  - londons_explore 4y ago
    Typically monitors buffer frames because the LCD matrix itself has a maximum and minimum refresh rate - and the user may provide an input signal outside that rate. Even so, the anti-ghosting compensation algorithms typically only work at one rate.

flyinghamster 4y ago

Now that sounds a lot like a video version of an audio issue that I have with my Android phone and a BluStream hands-free kit. When playing music from any source, there will be skips at long, random intervals. I could back up the song, play the suspect phrase over, and it would be perfect. It's almost like there's some sort of subtle clock mismatch somewhere that eventually can't be papered over. I've had it happen on more than one phone, and I'd also note that my Sony headphones don't skip.

jiggunjer 4y ago

This reminds me of a weird phenomenon in my parents living room: Our Samsung TV would stutter and colors would distort when lighting the candles with a lighter (one of those long-neck trigger models). Never figured out why but I suspect an EM pulse was created with each trigger "click", which affected the cable signal.

sitzkrieg 4y ago
those piezo sparkers definitely can cause some decent em pulses like any sparks really
- buescher 4y ago
  Yup. The poor man’s ESD gun.

garaetjjte 4y ago

>But of course if you used it with a PS4 then you didn't have any way to do that and just had to suffer this stutter every 20 seconds. You could splice cable DDC lines to I²C EEPROM programmed with patched EDID data.

sebastien_b 4y ago
Brilliant solution, but I would’ve dumped the defective-by-design monitor at that stage.
lreeves 4y ago
You can get EDID spoofers on Amazon for about 20$ for these kinds of issues.

d2wa 4y ago

(I’m the author.) I’ve tested with a different GPU and screen. The article focuses on the factors that made a positive impact on the problem. I’ve also swapped cables, disks, PSU, and other components.