You will never get full acceleration while using the Fake device-id for a Haswell IGPU setup, not while using the iMac17,1 SMBIOS.
You need to try one of the other Skylake framebuffers, to see if one works with your setup, you are already using a Mobile framebuffer, as they can drive a display. You will need to try one or more of the other Mobile framebuffers to see if any of them work with your IGPU. But without the Haswell device-id, that is a dead-end.
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As the screenshot above shows, there are no Skylake Desktop framebuffers that are meant to have a display connected. These Skylake Desktop framebuffers are all set to run 'Headless' (0 connectors) with a discrete GPU (AMD or Nvidia) driving the display.
As your IGPU is not natively supported you need to do one of two things:
- Install a compatible discrete GPU, so your IGPU runs 'Headless' as the iMac 17,1 SMBIOS expects.
- Change the SMBIOS to a system that expects to see just an IGPU, and hope you can get the fake device-id you use accepted. You may have better luck with one of the Desktop Kaby Lake framebuffers shown below.
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