Question MSI B450 Gaming Plus board and PCIe lanes

[ravin_29]

Hi,
I have a bit of confusion in understanding how PCIe lanes are consumed. I refer to MSI B450 Gaming Plus ATX board. Now if I correctly understand Ryzen CPUs support 20 PCIe lanes.
Here are relevant specs of this board. This board has 2 PCIe x16 and 4 PCIe x1 slots

• 1 x PCIe 3.0 x16 slot (PCI_E1)
o Supports x16 speed with AMD® Ryzen™ 1st and 2nd Generation processors
• 1 x PCIe 2.0 x16 slot (PCI_E4, supports x4 mode)1
• 4 x PCIe 2.0 x1 slots1

• PCI_E4 will run x1 speed when installing devices in PCI_E2/ PCI_E3/ PCI_E5 slot.

AMD® CPU
2 x SATA 6Gb/s ports1
1 x M.2 ports (Key M)1
Supports PCIe 3.0 x4 (AMD® Ryzen 1st and 2nd Generation/ Ryzen™ with Radeon™ Vega Graphics) or PCIe 3.0 x2 (AMD® Athlon™ with Radeon™ Vega Graphics) and SATA 6Gb/s 2242/ 2260 /2280/ 22110 storage devices

So if I install a PCIe x16 GPU and an M.2 NVMe SSD, does it mean that rest of the PCIe x1 slots can not be used?
Also it says PCI_E4 will run x1 speed when installing devices in PCI_E2/ PCI_E3/ PCI_E5 slot. So does it mean that in that case the PCIe slot 6 can not be used if E1, E4 E2 E3 & E5 are all used up?

Thanks.

 

[rgd1101]

chipset have pcie lane too
PCI_E1 and the m.2 is from the ryzen cpu. the rest is from the chipset

it mean max out at 5 pcie x1 devices(E2-E6) or 1 pcie x4 (E4) with 1 pcie x1(E6)

 

[ravin_29]

Thanks for the reply. As such specs do not clearly state if PCIe x1 are from the Chipset. Also this board has total 6 PCIe slots. The specs and manual are totally silent about slot E6

 

[AllanGH]

If you install an M.2 NVMe drive, you will lose the use of SATA_5 and SATA_6 ports.

Otherwise, you can populate the PCIe slots to full capacity in accordance with the following table, which primarily relates to the distribution of graphics cards in the system.

https://imgur.com/a/ib1PUUv

View: https://imgur.com/a/ib1PUUv

 

[AllanGH]

The specs and manual are totally silent about slot E6

Please see page 29 of your manual, from which the above table was taken.