Dell Precision 7540 and 7740 Owner's Thread

This is crazy. All Precision 7000 systems have the option to disable switchable graphics in the BIOS. It is in the video section, along with the option to switch the direct discrete video output mode. The exceptions would be if you don't have a dGPU installed at all, or if you have a display panel installed that is not compatible with the iGPU (I don't think that this has happened since the Precision M4800).

[Edit]
Here it is in the manual.
https://www.dell.com/support/manual...c5562f-45a1-4b00-a898-83e7db4cf84b&lang=en-us

 

They told me the Switchable Graphics is in the user manual, because there might be some other configurations that have it. But they were unable to answer me which one particularly and told me turn to sales department. Also he said there is nothing to replace in my notebook to make the option available.

I can only tell it has this builtin screen LG Philips LGD05F, but didn't find any datasheet for it.

 

In the bios, what is shown on the General -> System Information page, for Video Controller. If it says (none) the bios may be disabling the mux as it cannot detect a card. Maybe somehow it got a vbios installed for a 7550 RTX 3000?

 

The only situations that I am aware of where the display panel would make a difference here would be in the case where the iGPU can't work with the panel. For example, the M4800 got 1800p and 4K panels that the Intel GPU couldn't work with, and the M6700 had both 3D and 10-bit IPS panels that the Intel GPU couldn't work with. In this case, Optimus was forced off and the Intel GPU would not show in Device Manager and HWiNFO. You're seeing the Intel GPU so obviously Optimus is on.

You can check the vBIOS version by just firing up GPU-Z. (I'd be rather surprised if this made any sort of difference.)

This is where you are looking for the option, right?
@win32asmguy Can you take a snapshot of this page on your 7740 just to make sure we are not crazy here?



[Edit]
Just realized that you have 7540, not 7740. Still, if the option is there in the 7530 and 7740 then that is a pretty strong case that it should also be present in the 7540. Maybe a 7540 owner can chime in but I am quite certain that the option should be present.

If you used to have it and it is gone after the repair, I'd say its goofed up somehow... You should elevate to the supervisor and ask for the repair to be repeated or for a system replacement if they can't figure it out.

 

Check to see if the system bios properly recognizes the video card in the System Information section. It should say something like "NVIDIA N19E-Q1". If it does not detect the card, then it probably will not let you change the MUX settings, regardless of if the card it working fine in Windows.

Oh, maybe the third DGFF connector has poor conductivity and needs to be reseated? It carries display signal from the DGFF card to the USB-C port MUX so maybe it is in some kind of error state. Just a guess.

 

@Aaron44126 @win32asmguy Thank you guys for helping me with this!

In BIOS, it says...
dGPU Video: NVIDIA N19E-Q1
Video BIOS: GOP 1092 (where it comes from?)


In HW info, it says this video BIOS version: 90.06.39.00.6f


GPU-Z says this...


Oh and the case for replacement of my former mainboard+GPU was some PCI degradation error (degradation from x16 to x8). Strangely under that condition the Switchable Graphics option was there in BIOS.

 

Did the tech re-use the DGFF cables? That very well could be the part that failed causing the original degradation. If the bad one got switched from carrying PCIe data signal to the video output signal connector, that may be the issue.

 

I'm not sure about that, but the service protocol mention some DGFF2 item, so I hope so.

1. JYKVG 1 PWA,PLN,I79750,T,7540
   
2. 0PYG4 1 SVC,ALSOSHIP,7RMPY,06335
   
3. MWDWM 1 CRD,GRPHC,NV,N19E-Q1,DGFF2

 

I am not sure if the part # is same for the spares, but here is the original from the 7740 RTX 4000:


You may want to read the "Upgrade 7530 DGFF" thread here too, they talked about those connectors IIRC.

Mostly, you just need to escalate your service request with Dell. The MUX feature is available for all configurations of 7540 and 7740 that had a dedicated graphics card (AMD or Nvidia)

 

I see, I have also the NGRJG part in the original configuration, but not mentioned in the service protocol. So I guess DGFF cable wasn't replaced.

Anyways, thank you for confirming me that it's just my specimen of Dell 7540, which doesn't have the option in BIOS. I will try to escalate it.
I think the ProSupport arguing that it's not there because "it's not in our BIOS simulator either" is flawed. I guess the BIOS simulator is probably just universal for all 7540/7740 and doesn't count with any dGPU installed.