Source
r/buildapc•
_Ganon

Worried about PCIe 4.0, 2x NVME and a PCI 4.0 GPU

Solved!

Hey all,

I have the following parts:

  • Mobo: ASUS ROG Crosshair VIII Hero
  • CPU: AMD 3900X
  • NVMEs: 2x 1TB Samsung 970 Evo M.2 drives

And I was planning on upgrading to a GPU that uses PCIe 4.0. Did I make a mistake buying 2 NVME drives here, or is there a configuration where I can still have 4.0 x16 lanes for the GPU and use both drives? I didn't realize CPUs only had x amount of available 4.0 lanes until I started researching where to install the M.2 drives and now I feel dumb.

Posted Sep 9, 2020, 10:17 PM UTC

68
GodOfPlutonium•

ok so you see how your board has those 3 long x16 length slots. As long as you dont put anything in the middle slot, the top one will run at 4.0 x16.

Im guessing you probably read about the number of lanes the cpu has and noticed it only had 1 x4 group for nvme? The thing is theres also the chipset, which also has its own downstream lanes and your second m.2 is connected to that

4
_GanonOP•

That's exactly what I read haha. Got it, much appreciated.

2
chas1723•

Your nvme drives are pcie 3 so no issues. You can run them off the chipset without issue as it has it's own lanes.

3
_GanonOP•

Thank you!

1
Sprungnickel•

Even if those drive were gen4 one goes to the cpu and the other through the chipset and there’s not conflict to have 3 gen 4 pcie devices on x570

3
_GanonOP•

I actually was able to return them and got a single 2TB Sabrent Rocket which is PCI 4.0. Only like $60 more, why not

3
Sprungnickel•

X570 is made for that. Living the dream!

2
_GanonOP•

Yay! Glad to hear that. So excited to build this thing. Thanks!

1