MSI B450 Mortar Max pcie lanes and nvme ssd

[RainingTacco]

The board have two M2 slots, but im confused whether it will slow down GPU when both are used. Here's the spec page https://www.msi.com/Motherboard/B450M-MORTAR-MAX/Specification

One Pcie 3.0x4 is provided by CPU as it seems[ryzen supposedly have 24 lanes, shouldnt be able to run two ssds?]. But the other one says its provided by chipset, but it says "PCI_E4 slot will be unavailable when an M.2 SSD is installed in the M2_2 slot.", where "PCI_E4" slot is "PCIe 2.0 x16 slot (PCI_E4, supports x4 mode)". So when installing that second SSD, will it decrease my primary PCIE 3.0x16[the one for gpu] speed to x8, because of using PCIE 2.0x16 slot by SSD? That second SSD will basically work like installing a PCIe SSD in the PCie 2.0x16 slot right? Can anyone give me a good resource with PCIe and SSD interaction explained? A 101 guide for dummies? 

[bcn.jmontuya]

Up! we need answers :)

[balderm]

I got that motherboard, but i don't have 2 NVME drivers to test it, but i can tell you that the Instruction manual states that the bottom PCI-E slot will be disabled when 2 NVME drives are installed, so the top PCI slot for the GPU will not be affected.