X570 PCie 4 usage, need help

Josu · 14 Jul 2019 at 14:54

Hey, i am thinking to go for X570 board, because i want to use multiple nvme ssds in system.
I want to get rid of sata ssd and extra wires.
So i was thinking to buy expansion card for 4 nvme ssd and make raid 0. I guess with GPU this card will run with pcie4 x8 speed (both GPU and this card) and this speed should be enough to use all this nvme ssds. Am i right, or i will bottleneck them?

Jamin280672 · 14 Jul 2019 at 19:25

Josu said:
Hey, i am thinking to go for X570 board, because i want to use multiple nvme ssds in system.
I want to get rid of sata ssd and extra wires.
So i was thinking to buy expansion card for 4 nvme ssd and make raid 0. I guess with GPU this card will run with pcie4 x8 speed (both GPU and this card) and this speed should be enough to use all this nvme ssds. Am i right, or i will bottleneck them?

If you get something like an MSI Godlike, you'll get 3 nvme ports on the board, they all run at full speed, and you'll also get an nvme expansion card the will take another 2 nvme drives which will run at full speed to, but using this card will reduce the speed of your GPU to x8.

The CPU provides 20 PCI-e 4.0 lanes, 16 for the GPU and 4 for the 1st onboard nvme drive........if you use the nvme expansion card, then you get 8 lanes to the GPU and 8 lanes to the expansion card 2 x 4 lanes for each nvme on the expasion card.

Then on top of that, the chipset also provides 20 PCI-e 4 lanes, 8 for the other 2 nvme's on the board and the rest for everything else, SATA, USB etc.

Josu · 14 Jul 2019 at 21:03

Yes, x8 PCI-E 4th gen should work like x16 gen 3. So basically GPU will be working on full speed. But 700 for board, no way

Jamin280672 · 14 Jul 2019 at 21:54

Josu said:
Yes, x8 PCI-E 4th gen should work like x16 gen 3. So basically GPU will be working on full speed. But 700 for board, no way

I dont think it will work that way, a PCI-e 4.0 GPU still needs 16 lanes to run at full speed.

If you use a PCI-e 3.0 card in the board, it will just run at PCI-e 3.0 mode x16 or x8, you'll just loose the extra bandwith that PCI-e 4.0 delivers, it wont be converted to run the card at full speed using 8 lanes only, think of it as its only using half of those contacts that you can see in the slot, because the other half of those contacts get switched off and diverted to the other PCI-e slot with the x8 M.2 expander card in it.

Josu · 15 Jul 2019 at 04:21

Jamin280672 said:
I dont think it will work that way, a PCI-e 4.0 GPU still needs 16 lanes to run at full speed.

If you use a PCI-e 3.0 card in the board, it will just run at PCI-e 3.0 mode x16 or x8, you'll just loose the extra bandwith that PCI-e 4.0 delivers, it wont be converted to run the card at full speed using 8 lanes only, think of it as its only using half of those contacts that you can see in the slot, because the other half of those contacts get switched off and diverted to the other PCI-e slot with the x8 M.2 expander card in it.

Thank you for explanation