Discrete / Integrated Graphics lags. How to connect external monitors on P52/P72

[Lenovo4K]

Hi,
I received my new P72 (P2000 Graphics) and I have a major issue with the connection of external monitors.

My former laptop (MSI GP2) had HDMI and miniDP as outputs. I ran my former laptop with

• inbuilt 1080p (native)
• external projector (HDMI 1080p - cloned from inbuilt)
• external Monitor (miniDP 4K - extended view)

Everthing was setup and configured by Intel software, therefore everthing was done by integrated graphic chip. Once I started to run a game, the discrete graphic cards took over to render the game.

On my new P72, I used same connection as above with the only difference, that I have a inbuilt 4K screen. Somehow, the entire system is extremly laggy with asynchronous audio. The two external devices are not ran by the integrated graphics but with the discrete. The 4K picture from my inbuilt is somehow scaled to 1080p for my projector ( I didnt even know, that this was possible and I thought, that this might cause the problem. After changing to 1080p on my inbuilt, I still had same issue).

How do I ran the external devices on the integrated Graphics?
Do I need to use Thunderbolt?
Why is the connection of external monitors through discrete graphics so laggy?

[bobbie424242]

Unfortunately, you can't run external monitor ports (HDMI, DP) on the integrated graphics as they are wired to the dGPU. That also apply to Thunderbolt 3 connected displays,
It would be interesting if you made a video of the laggyness so visitors of this forum can better understand the problem.

[Lenovo4K]

I can try to make a video but this will take some time.

When my laptop (4K Resolution) is connected to a 1080p beamer ->Clone Modus:
Who is scalling the 4K into 1080p? Where can I find options about that scalling?
When I play a youtube video during above mentioned setting, I see lags and asynch sound. When I switch to Fullscreen video mode, that lags get heavier and CPU Usage also increases.

The above issue might caused be the scalling calculation. At least, that is, what I thought but when I switch to 1080p on my internal screen, I observe similiar issue with less lags.

[Lenovo4K]

 Some further questions:
i) When I connect and clone my laptop P72 with 4K to an external monitor with 1080p, somehow the resolution of 4K is scaled to 1080p. How is this function called and where are the settings for that? I always thought, that this is impossible in hybrid mode. Nvidia has a similiar function for games called DSR | Dynamic Super Resolution.
ii) Where can I find the former nview desktop manager function in current drivers?
iii) When I look into my friends laptop (P50). I can see, that his nvidia software shows three monitors (1x internal + 2x external). Further, his intel software only shows the internal monitor.
How come that with my similiar setup, I only see external monitors in nivdia software? The nvidia software doesnt allow me to arrage position or choose between clone and extend mode. I can only do some of the settings in windows 10 options.

[bobbie424242]

Although I rarely use an external monitor, I tried to reproduce the laggyness you describe and...I could reproduce it.

I connected a 4K monitor to the mini-DP port (connecting it to Thunderbolt gives the same issue), cloning the laptop panel. Then smooth scrolling in Firefox was not smooth anymore and rather jerky. Also, animations restoring windows from the tasbar weren't sometimes as smooth as usual.

I thought at first it was maybe due to the "balanced" power plan so I tried with everything set on performance, but it did not change anything. I tried different scaling options (default is 250%) and it did not change anything either.

Next I went into BIOS and set it to "Discrete Graphics" (that's in Config > Display > Graphics device) to entirely bypass the integrated GPU and...bingo ! Any combination with the second monitor (duplicate, extend, second screen) was smooth as silk, as you'd expect. Conclusion: there is a severe performance issue in "Hybrid graphics" mode. Whether it is a Windows, NVIDIA or Intel issue in drivers, impossible to tell. Hybrid Graphics is quite a complex thing and kind of a frankenstein thing.

So the solution for now is to use "Discrete Graphics" which is not really a problem if your laptop is always plugged to power.

[Lenovo4K]

After trying many different configurations the last two days, I finally found the issue. It definitely comes down to the communication between the NVIDIA and Intel driver. I have the P72 with P2000 graphic and a 4K screen. Further, I have a 4K external monitor and a 1080p beamer.

• No issue at all in any configuration ( clone or extend mode ) when BIOS setting is discrete graphics
• In hybrid mode, simply cloning the inbuilt screen to any external device results in heavy lag. Playing a full screen youtube video is impossible.
• In hybrid mode, the inbuilt screen is always run by the INTEL driver and any external device (HDMI, DP or Thunderbolt) is run by NVIDIA driver. This is the source of the problem.
• In hybrid mode, setting up my 4K external monitor as main monitor ( Desktop ) and cloning it with my beamer, thus leaving my inbuilt monitor as secondary device, also creates No lag. In this case NVIDIA is creating the clone modus with two external devices and the externals are configured as main (desktop) monitors. The inbuilt in this case would be simply an extension of dektop.

I could leave my notebook to discrete mode but it also consumes a lot more energy this way. I travel occasionally and would like to have long battery life. Changing the mode means, that I must always enter the BIOS, which is annoying because I almost never shutdown the laptop. I mostly use sleep mode.

If there is an easier way to change between discrete and hybrid mode, please let me know.

[ajakab]

hi,
i am suffering same thing on my new Thinkpad P1 too - unbelievable ...
working with an external thunderbolt dock and a 4k display connected. Whenever i switch to the external monitor the stuttering occurs.

i fixed it by creating a BAT file on my desktop which does the following with admin previleges :
"taskkill /f /im dwm.exe"

this restarts the service and fixes the stuttering on my setup

[ve2mrx]

Hi Lenovo4K,

Have you tried to leave the BIOS in hybrid mode and set the default GPU in NVIDIA control panel > Manage 3D settings > Preferred Graphics Processor to High-Performance NVIDIA processor? That should force the dGPU to manage the internal display by default.

Test to see if you still get lag. If not, you have an easier solution than switching in BIOS...

Just a thought,

Martin

P.S. I have a P52, but haven't gotten to make it my main system yet. I will have to test it with my two external monitors at some point... :-p

[Lenovo4K]

---

@ve2mrx wrote:

Hi Lenovo4K,

Have you tried to leave the BIOS in hybrid mode and set the default GPU in NVIDIA control panel > Manage 3D settings > Preferred Graphics Processor to High-Performance NVIDIA processor? That should force the dGPU to manage the internal display by default.

Test to see if you still get lag. If not, you have an easier solution than switching in BIOS...

Just a thought,

Martin

P.S. I have a P52, but haven't gotten to make it my main system yet. I will have to test it with my two external monitors at some point... :-p

---

 
That doesnt help because in Hybrid Mode the internal screen is forced through Intel driver. The setting you describe above is just for application. You can select the GPU for applications but not for windwos in general / Desktop Window Manager. Intel and Nvidia still need to work at the same time.

[ve2mrx]

Ah, thanks for the info! I didn't know Intel would still handle the built-in screen.

That could explain what appeared to be corrupted screen items in the game Tacoma. However, it only added to the game, as you deal with what appears to be a damaged AI ;-)

Thanks!
Martin