M.2 on Rock Pi 4

#1

Hello,
are all Rock 4 boards come with 4x lane m.2 slot? I can’t confirm that on wiki or any official info :confused:
When it’s limited to 2x?

#2

All ROCK Pi 4, 4A, 4B, 4A+, 4B+, 4C+, are 4x lanes PCIe, M.2 M key.

1 Like
#3

Pcie 2.1 x4 I think on all as opposed to later SOCs with Pcie 3.0

#4

Thanks for clarification, there is no clear info on some of models about that. This makes this board perfect for me, do You know when c+ will be available again? it’s out of stock now :frowning:

#5

This is interesting too, 3.0 2x should be about the same as pcie 2.1 4x. I need to check that on rock 3a vs other boards to see if it can get full speed of my nvme.

#6

Depends on what your using as devices will clock down but if you have a x2 device then only x2 will be used.
So if you where thinking about the x5 Sata adapter with the JMB585 chip then its x2 Pcie 3.0 so will clock down to x0.5 speed of Pcie 2.1 of 2x lanes but most Nvme are x4.
So prob a Rock3 is preferential with x2 Pcie 3.0.

#7

I’m just looking for best nvme performance in sbcs. Today only few boards gives reasonable support on m.2 and this is great bottleneck for io. Newly released vim4 has m.2 with 1x pcie 2.x so it should limit almost every m.2 card, if rock4 has 4x m.2 slot then it’s just 16x better :slight_smile:

#8

Yeah the Pi4CM and Vim3/4 are pretty awful for pcie bandwidth all I was saying if sata the Rock3 is actually a better buy as the sata cards are pcie3.0 x2.
With a nvme on x4 pcie2.0 or x2 pice3.0 the bottleneck at least most of the time will be the cpu so prob doesn’t matter unless like you say its a Pi or Vim.
Its great that they can use nvme but still the cpu would not be all that noticeably different in running than eMMC but things with tech and prices are so that you prob could pick up a nvme cheaper as relatively eMMC we can get isn’t all that cheap.