Question ASUS X99 Deluxe II PCIE lane allocation with 3 expansion cards?

[Raptor55]

I have an ASUS X99 Deluxe II with an i7-6800k 28 lane CPU.

I currently have my RTX 2070 Super installed in PCIEx16_1,
an NVME ssd expansion card in PCIEx16_3,
and the included thunderbolt expansion card installed in PCIEx16_4.

The bios says the GPU is linked with 8 lanes while the other 2 cards are linked with 4 lanes each.
However, if I remove the thunderbolt card from the 4th lane the gpu uses all 16 lanes of its slot.

I have no M.2 or U.2 drives installed that might draw additional lanes from the slots, so why is my GPU being limited to 8 lanes when there are still 12 cpu lanes available?

Is there any way to get the gpu up to 16x with the ssd and thunderbolt card installed as well?

For reference, the manual for my board:
https://dlcdnets.asus.com/pub/ASUS/mb/LGA2011/X99-DLX_II/E11357_X99-DELUXE_II_UM_WEB.pdf

 

[helpstar]

USB and SATA ports are sharing bandwidth with the PCIe lanes as well

16_1 -> x8
16_3 -> x8
16_4 -> x8

set the 16_4 to x4 or try installing the TB card in slot 5

only real way would be installing a 40lane CPU

 

[Raptor55]

Thank you for the assistance helpstar.

The bios only has settings for pcie gen for slots 1,3, and 4, not lanes.
However, it reports 3 and 4 as linked at 4x.
The Intel tb setup in the bios has no option for the 5th slot so I can't put it there.

I don't need some of the sata and USB ports, and can disable them. Would that free up lanes or am I out of luck?