x570 & b450 w/ 3900x - pcie lanes and sata ports

[mechanicalfluff]

Hey all - just upgraded 2700x to 3900x. I haven't bought a x570 board yet before i figure this out.

I had issues with the b450 and 2700x using an nvme drive and two gpu's losing sata ports, running gpu's in 8x and 4x etc.

I'm just thoroughly confused about what is actually usable in these boards. Coming from x79 and 40 lanes, the 2700/b450 upgrade threw me for a loop. I was just used to plugging whatever would fit in and it just working no matter what.

Sorta TLDR:
Can I run an nvme ssd at 4x (pcie3) along with 2 gpu's at 16x without compromising sata ports or lane speeds in x570?

thanks folks!

[mariushm]

No.

 

Your cpu has 24 pci-e lanes.

4 go to the chipset

4 go to the first m.2 connector

16 go to first pci-e x16 slot.  These 16 lanes can be automatically split into 2 x8 slots if you insert two video cards.

 

The chipset talks to the cpu using those 4 pci-e lanes. In turn, the chipset creates additional pci-e lanes for pci-e slots, or uses those lanes for other things. The chipset can create up to 8 pci-e lanes, which can be arranged in various combinations of x1, x4 or x8 .... anyway, just look at the picture below.

 

[mechanicalfluff]

exactly the graphic i needed. thank you very much!