<< Solved >> PCIE 4x don't work on Z370 HD3P (solved)

[BenCharbo]

Hello everyone, i've just discovered today that my pcie 4x don't work and i don't know why although every other pcie works well, i've tested with 3 different cards, a UAD duo pcie, a firewire pcie card, and my brand new fenvi fv1919 pcie card.

All the cards work perfectly in other pcie 1x slot.

Any idea ?

my mobo is a Gigabyte z370 hd3p and i run Mojave 14.4

 

[jaymonkey]

@BenCharbo,

Don't forget about the 20 PCIe lane limitation on all Intel Desktop Class CPU's.

Most x1 slots and some x4 slots are serviced by the PCH (they don't count to the 20 CPU lane limitation), it depends on the motherboard and manufactures implementation. Some M.2 slots share lanes with a x4 PCIe slot, and some SATA M.2 slots share a channel with a standard SATA connector on the the PCH.

Everything connected through the PCH will have to share x4 bandwidth to the CPU.

Check your motherboards manual, it should tell you which lanes are x16 and which ones are x8 and which PCIe slots share PCIe lanes with a M.2 slot. There is usually a block diagram which explains it.

On motherboards that have PCIe lane switches, sometimes installing the GPU in a x8 slot will free up some lanes that can be used by other devices.

Cheers
Jay

 

[BenCharbo]

i've finally understood

"The PCIEX4 slot shares bandwidth with the M2Q_32G connector. The PCIEX4 slot will become unavailable when an SSD is installed in the M2Q_32G connector."

thanx @jaymonkey