08-07-2019 09:55 AM - edited 08-07-2019 10:01 AM
Recently I migrated from years of using Dell laptops (this is relevant to my post) to a P1 w 32g ram, quadro p2000 gpu, ssd, etc...
I'm having an issue when I'm docked and using external monitors, all video playback is laggy/choppy. Dragging windows around the screens is laggy/choppy.
This doesn't happen if I'm only on the laptop monitor.
I've read through several other related threads here and they suggest to disable the intel integrated graphics in BIOS. But everyone I saw that did that resulted in those folks not being able to get into their BIOS at all as noted here. They could use their external monitors and get into Windows OS but since the BIOS displays only on the laptop monitor, that seems to get disabled when that setting is toggled. So... I'm not going to try that option. (Really Lenovo?)
Some things to note. Back when I was on my last Dell Laptop (Precision 5520 with similar specs), the laptop ALWAYS used the integrated intel graphics unless you had apps that specifically were set to use the discrete GPU. What that meant was that even when using external monitors, the intel gpu was active and being used. This P1 behaves differently. When I plug into the docking station and use the external monitors, the intel gpu is disabled entirely. If I only use the laptop monitor, the intel gpu is used.
So, the thing is... when I'm on the external monitors, it appears that I'm only using the nvidia gpu anyway, no intel gpu is in the mix. So why the laggy/choppy display?
The other very interesting thing is... if I restart the laptop, the issue clears up on the subsequent bootup. The laggy/choppy display issue completely goes away and everything is butter smooth. Now, if I perform a "shutdown" and then turn the laptop back on, I see the issue again. I have to do a "restart" to get back to smooth display. Takeaway: From a cold start, the laptop has the issue, from a hot restart, no issue.
Ok, all that said, what can I do to troubleshoot and fix this?
08-07-2019 10:03 AM
I think the issue when you see the chopy display is when it is using the Intel GPU. See my other thread.
When I forced it to go dedicated. This issue has never happened again. However for the first 2-3 months of using the laptop it wasn't an issue. I think its a driver/windows update that somehow messes up the issue. When using an external monitor I beleive it should always go dedicated. But its like after some update it doesn't make the switch to dedicated. Its really to bad as I love the laptop.
If yo are using an external monitor and it is laggy. Try switching it to mirror displays. You will see the laggy go away. Sometime switching it back to external will make it stay that way and sometime it will come laggy again. This issue is really frustrating. However I would love to have the issue back and have the use of my laptop display lol.
08-07-2019 10:10 AM
08-07-2019 01:22 PM
Ok, so I've found a solid work-around for this issue. I disabled "fast startup" per this article and the issue seems to be fully resolved. Now, that doesn't explain why this is an issue when "fast startup" is enabled but I'll take this as a very nice start.
I'll leave this unresolved for now in the hopes that someone might be able to come up with an actual solution.
08-07-2019 02:59 PM - edited 08-07-2019 03:01 PM
The Chopyness is caused by Optimus (aka "Hybrid graphics") and likely what is a bug in Windows in conjunction with it. That's why it does not happen in "Discrete graphics" mode which disable the iGPu thus Optimus. Interesting that disabling "fast startup" is a workaround for you, this is the first time I hear about it. Killing dwm.exe while the second monitor is active can also sometimes fix it.
08-08-2019 08:58 AM - edited 08-08-2019 08:59 AM
I just read up on Optimus and am totally confused about how it is implemented. In my case, on this P1, when I'm not plugged into the dock, the intel integrated graphics is in use unless I have specific apps that use the nvidia p2000 gpu. That to me seems like what "Optimus" is designed to do.
Now, when I plug the laptop into docking station which has three external monitors on it, the laptop switches 100% to the nvidia gpu and the intel integrated graphics becomes totally disabled. I did nothing to set it up this way and if I go over to coworkers with the same laptops, docking stations, etc... they are showing the same behavior.
I guess my question is: Shouldn't we be seeing the same intel integrated graphics / nvidia gpu "on demand" behavior EVEN when docked? Why is it going to a fully nvidia gpu dedicated setup when docked? Is that by design? If so then that seems to contradict bobbbie424242 statements above because the choppiness IS occurring when I'm in "discrete graphics mode". See my OP. The choppiness only occurs when I'm docked and on external monitors... aka discrete graphics mode.
08-08-2019 09:11 AM - edited 08-08-2019 09:13 AM
"Discrete graphics" mode, refer to the BIOS setting allowing to either function in iGPU+dGPU mode (aka Optimus) labelled "Hybrid graphics", or in dGPU only mode (aka "Discrete mode").
In "Hybrid graphics" mode, Windows see 2 graphic cards while in "Hybrid mode" it only see the dGPU. So "Hybrid graphics" mode is not what you think it is, unless you changed in BIOS and set it to that.
Optimus ("Hybrid graphics") is more sophisticated than when it is disabled, hence has more of a chance to cause potential problems.
Now, all the external video ports (that includes DisplayPort over Thunderbolt 3) are managed by the dGPU, because these ports are wired to it. So yes, that's entirely by design and your external monitors are always managed by the dGPU.
Hope that clears up denonimation of things a bit.
08-08-2019 09:20 AM
Yes, thank you. That really clears it up. And for my part, I have left that setting in BIOS as the default "hybrid" and not the discrete only option.
09-12-2019 11:34 PM - edited 09-13-2019 04:07 AM
No way M123Marv!
This "switching it to mirror displays" freaking works! Have had lag since the beginning on my highend P1, and mirroring makes it go away. Thanks!
(very confused though why this works....)
09-12-2019 11:35 PM