AN515-46-R8H3. External Monitor is using IGPU instead of DGPU.

Hi, my acer nitro laptop is AN515-46-R8H3.

I do have an external monitor ViewSonic VX2758A-2K-PRO-2 27” 2K 185Hz.

When I connect my laptop to my external monitor using HDMI 2.0 cable. Everything's great, maxed out the display settings to 144hz. Mux switch is turned on (discreet GPU only) I also checked the NVIDIA activity and it says that my external monitor is connected to my DGPU (discreet GPU) Nvidia RTX 3070.

Then I decided to buy a USB-C to display port 1.4 from UGREEN. since I want to try and use the one and only slot of USB-C at the back of my laptop and also to maximize the refresh rate to 185hz. I have also checked the specification of the USB-C socket at the back of my laptop. I have highlighted the model of my laptop. please see the SS below:

When my USB-C to Display port 1.4 arrived from UGREEN. I immediately tried it using the
DP 1.4 cable that came from the box of my ViewSonic monitor. It is working, maxed out the display refresh rate settings to 185hz. The major issue is it's connected to my IGPU (laptop internal graphics) Not to my DGPU Nvidia RTX 3070.

I have tried several troubleshooting already:

from NVidia settings/physx i prioritized the use of my DGPU instead of IGPU.
I have tried turning off my MUX switch then restart. Still the same issue. Turned it back on again after.
I have tried to reseat the DP 1.4 cable including the usb-c dp cable from ugreen.
all my drivers are updated

After doing these troubleshooting. Still got the same issue. My external monitor is still connected to my IGPU instead of DGPU.

Hopefully someone can explain/help me further. Thank you.

[Edited the thread to add model name to the title]

Accepted answers

StevenGen

https://community.acer.com/en/discussion/comment/1287771#Comment_1287771

Yes, that is correct, the TBT4 ports are all connected directly to dGPU while the USB-C port is connected directly to the iGPU. To get the 185Hz refresher rate that your monitor has change the HDMI 2.0 cable to a HDMI 2.1 and try the HDMI connection again, as you should be getting the 185Hz refresher rate through the dGPU also. Forget about connecting the external monitor through the USB-C port with a USB-C to DP cable. And use the HDMI 2.1 port and take note of what the HDMI port 2.1 that your laptop has can do below. Have a look at this hub "A Technical Demonstration of the Plugable Thunderbolt 4 Hub (TBT4-HUB3C)" could be a solution.

Note: HDMI 2.0 and 2.1 can support up to 240 Hz in 1080p resolution. It also supports 144 Hz in 1440p resolution & 60 Hz in 4K resolution. But if you need a more refresh rate in 4K, you will have to use HDMI 2.1 cables that can support up to 120 Hz in 4K & 60 Hz when using 8K resolution.

If this answers your question and solved your query please "Click on Yes" or "Click on Like" if you find my answer useful👍

All comments

StevenGen

https://community.acer.com/en/discussion/709484/an515-46-r8h3-external-monitor-is-using-igpu-instead-of-dgpu

As the Nitro AN515-46 does not have a TBT4 port and the only way to connect an external monitor directly to this laptop HDMI 2.1 port (not HDMI 2.0) or through the USB Type-C Port that supports a DP 1.4 graphics output which is another way to connect a monitor to this laptop.

Note: HDMI 2.0 and 2.1 can support up to 240 Hz in 1080p resolution. It also supports 144 Hz in 1440p resolution & 60 Hz in 4K resolution. But if you need a more refresh rate in 4K, you will have to use HDMI 2.1 cables that can support up to 120 Hz in 4K & 60 Hz when using 8K resolution.

As you have gotten and connected the monitor with a USB-C to DP 1.4 adapter cable, you need to go to the NVidia Control Panel and allocate all the games and software's that you want to only use the RTX3070 gpu, as that is how the dGPU will be allocated to use the RTX3070 gpu, try that. Good luck and hope this helps you out.

These are all the USB-C and DP 1.4 specs that the Nitro AN515-46 laptop has in more detai:

If this answers your question and solved your query please "Click on Yes" or "Click on Like" if you find my answer useful👍

EnZone2974

Thanks for the answer @StevenGen

I just have a follow-up question.

does the USB-C port that I have here on my laptop is directly connected to my IGPU? However, a Thunderbolt 4 (TBT4) is directly connected to a DGPU? This is based on my research since you clarified that my laptop does not have a TBT4, which is unfortunate that I don't have a TBT4 port based on the screenshots you provided.

Another thing is the external monitor that I'm using does have an HDMI 2.0 port and a DP 1.4 port only. Well my laptop does have an HDMI 2.1 port, Should I buy an HDMI 2.1 cable and use it instead? will it have an increase output performance on my external monitor? Thanks

EnZone2974

hello @stevengen. Thanks for the answer.

I just want to clarify some info that you provided.

does a TBT4 and a USB type C port that I have on my laptop is 2 different thing? I have also done research about it. TBT4 is connected directly to DGPU while my USB-C port is connected directly to IGPU. Am I correct?

And to answer also some of the details you provided:

I'd love to use an HDMI 2.1 cable instead because my laptop does have a socket of HDMI 2.1 , unfortunately my external monitor does have an HDMI 2.0 socket only and a DP 1.4 socket.

If I use an HDMI 2.1 Cable. Considering the situation I have, do you think is it worth it to buy an HDMI 2.1 cable instead? Thanks

StevenGen

https://community.acer.com/en/discussion/comment/1287771#Comment_1287771

Yes, that is correct, the TBT4 ports are all connected directly to dGPU while the USB-C port is connected directly to the iGPU. To get the 185Hz refresher rate that your monitor has change the HDMI 2.0 cable to a HDMI 2.1 and try the HDMI connection again, as you should be getting the 185Hz refresher rate through the dGPU also. Forget about connecting the external monitor through the USB-C port with a USB-C to DP cable. And use the HDMI 2.1 port and take note of what the HDMI port 2.1 that your laptop has can do below. Have a look at this hub "A Technical Demonstration of the Plugable Thunderbolt 4 Hub (TBT4-HUB3C)" could be a solution.

Note: HDMI 2.0 and 2.1 can support up to 240 Hz in 1080p resolution. It also supports 144 Hz in 1440p resolution & 60 Hz in 4K resolution. But if you need a more refresh rate in 4K, you will have to use HDMI 2.1 cables that can support up to 120 Hz in 4K & 60 Hz when using 8K resolution.

If this answers your question and solved your query please "Click on Yes" or "Click on Like" if you find my answer useful👍

EnZone2974

Thanks @StevenGen , do you have a documentation or a link that acer shows that it is how it works in terms of their hardware? that the USB-C port is connected directly to IGPU while the HDMI is the only thing that is connected to DGPU.

Reason why I'm curious is because for other laptop brands, It's different, some other laptop brands usb-c, DP port and hdmi port are all connected to DGPU. Thanks

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