Welcome to the Dell Community @goni4ka 

As you should know there is no option in the BIOS to turn off/Disable the graphics card.

At least not one that I can see.

Best regards,

U2

@U2CAMEB4ME is there any other way to disable this slot without removing card? 

F2 during restart to enter UEFI BIOS settings. Video -> Switchable Graphics / Optimus

Manual

AMD:

NVIDIA:

@goni4ka 

You should be able to go to "Device Manager" and disable it there???

Regards,

U2

@pb79 thanks, but i dont have it in bios, only lcd brightness

Welcome to the Dell Community @pb79 

I see the M4800 has a similar BIOS as the M4700.

But the OP has an AMD FirePro not NVidia..

I did not know by turning off Optimus Technology that it would disable the card also???

But I guess that you have tested it just to make sure???

@goni4ka 

What version BIOS do you have???

Regards,

U2

There is no such thing as Disable Mobile PCI Express Module (MXM) slot.

You have to remove the card.

Currently I do not have M4700 (it was about year ago) but I switched between Intel and AMD Fire Pro discrete GPU (W10). Please update UEFI first to the latest version.