BIOS disabling iGPU when a dGPU is present - Acer Aspire XC-1660G-UW93

JasonStern
JasonStern Member Posts: 8

Tinkerer

Bought an Acer Aspire XC-1660G-UW93.
Installed a discrete GPU.
For some reason, the BIOS is force disabling the Intel HD730 integrated GPU.
Is there a BIOS image that allows dual graphics? If so, can someone provide me with a copy?
Acer support isn't being helpful, likely due to me buying the PC (from them) refurbished. So if someone still has a warranty that they are willing to honor, could someone ask for me?
Thank you!

[​//Edited the content to add model name]

Answers

  • ttttt
    ttttt Member Posts: 1,947 Community Aficionado WiFi Icon
    @JasonStern

    Whenever a dedicated GPU is inserted to the x16 slot, the onboard UHD730 integrated graphics will be disabled.

    It is your choice whether to use either the discrete graphics card or the UHD730, not both.
  • JasonStern
    JasonStern Member Posts: 8

    Tinkerer

    Right - that is the problem. And the problem is caused entirely because the BIOS is force disabling the Intel HD730. There is no technical reason why half of the i5's silicon needs to be disabled due to the presence of a discrete GPU. The Intel i5-11400 is perfectly capable of power management, and Windows has supported dual graphics dating back to at least Windows 7.

    If Acer doesn't want to officially support it for no valid reason, is there at least a chance the source code to the BIOS could accidentally fall off the back of a truck so the community can add back the missing device support?
  • ttttt
    ttttt Member Posts: 1,947 Community Aficionado WiFi Icon
    @JasonStern

    It is not the problem with Acer's machine, it applys to the general PC world, and must have technical reasons.
    That must be related to how the PC utilize the video resources.

    Windows started supporting dual monitors since Win 98.
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  • Leostat
    Leostat ACE Posts: 3,043 Pathfinder
    Check the PCI bus they are sitting on :) With that dell they are on two lanes so its easy to do as its just two devices, with some mobo vendors rather than having a seperate X16 lane, they only have one PCI lane hooked up, bifurcated into two lanes, so if you insert a GPU it ends up stealing the lane (its stupid and annoying, vendors that do that 👎)
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  • Leostat
    Leostat ACE Posts: 3,043 Pathfinder
    So its not shared all the time but sometimes rather than the bus being split out into the GPU / PCI, hthey just plonk the iGPU and the pcie on the same lane to save traces which is why its worth checking :) i will give it a look in the service manual to see if its a tech reason or just lazieness on the board part!

    however it is much less common now as CPU's have more lanes available. I guess manufacturers have just not adapted.
  • Larryodie
    Larryodie Member Posts: 1,653 Community Aficionado WiFi Icon
    Wondering if you have the latest bios installed. RO1-A4
  • billsey
    billsey ACE Posts: 34,101 Trailblazer
    Yeah, Dell does some magic to allow the dual GPU thing to work, most other manufacturers don't do that...
    Click on "Like" if you find my answer useful or click on "Yes" if it answers your question.
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  • JasonStern
    JasonStern Member Posts: 8

    Tinkerer

    Yes, I am running the latest BIOS. Updating was one of the first things I tried, hoping that someone else already encountered this and got the option enabled.

    Most BIOS on consumer PCs disable the iGPU when a dGPU is present. I guess it's to not confuse people about where to plug the cables in? Disabling it might help burst mode CPU performance with respect to peak TDP since half of the chip is disabled. But given limited GPU options for the XC-1660G-UW93, it would be nice to have all of the compute performance that I can get.

    On the embedded platforms I have worked on, we would have to manually modify the BIOS to allow both GPUs to run concurrently. Simple enough change and encouraged by Intel. After all, we paid for the HD730!

    The PCIe lane theory is fun. And if I was trying to run two dGPUs, that could explain it. But the HD730 doesn't use any PCIe lanes. It's physically built into the i5's dye, and uses the same memory bus and controllers to access physical RAM as the CPU. The HDMI video outputs for the HD730 are run completely independent of the dGPU's outputs.

    And to be clear - I don't want hybrid graphics (switching the active GPU but keeping monitors connected to the same video ports - common in multi-GPU laptops). I want both the dGPU and iGPU enabled concurrently so I can run additional monitors and distribute compute shader work. If you go into the Intel specific section in the BIOS menu, you can see the option. It's just force disabled for no real reason.

    Gabriel from support replied with:

    Thank you for the message. Please be advised that you cannot run both in the same time. You are able to select which program or games run on the integrated or the dedicated.

    ...which isn't helpful and rather confusing. I guess I could try reaching out to American Megatrends, but I doubt they'd do anything without Acer's approval.
  • rockdude
    rockdude Member Posts: 3 New User
    Having the same problems here.  1 month into operations and I wished I purchased some other unit.  Contacted Acer and they want to have the unit to fix it.  I don't know about that.

  • billsey
    billsey ACE Posts: 34,101 Trailblazer
    They won't be able to fix it, since it is working as designed. You can have the onboard video or a GPU with video, not both.
    Click on "Like" if you find my answer useful or click on "Yes" if it answers your question.