Multiple USB 3.0 to gigabit dongle performance vs. PCIe

Networking Networking Hardware
,
1

As I’m getting started with my homelab (mainly a HP SFF PC with a raspi here or there) I wanted to set up some vlans and play around with ipfire/openwrt VMs, to do this, I need more than the 1 gigabit Ethernet port integrated into the systems mobo. I have considered getting some PCIe network cards, but this machine also has a bunch of USB 3 ports. I was wondering what sort of performance loss (latency and throughput) I would experience if I used some USB 3 to gigabit dongles instead of a PCIe to gigabit card. How many dongles could I use before I start to overwhelm my USB controller? Also, for context, I’m a college student so I’m trying to do all of this as cheaply as possible.

Thanks for the advice!

2

Just get a quad pcie card if you have the lanes still.

1 Like
3

Unfortunately I only have 1x slots available on this mobo, so it would have to be a few dual port cards.

4

Just make the single port a trunk, no need to put each vlan on a physical interface.

3 Likes
5

x1 as in one slot … or x1 as in single lane or x1 as in slow and old PCIe v1.x ?

Theoretically you could get a 10G or a 40G card+ and a switch with a fast uplink

6

Well on USB 3.0 you would have a limit at 5Gb/s so 500MB/s, that is theoretical max, with overhead you’re at about ~450-460MB/s so if you get about 5 dongles you’re pushing it to the theoretical max but with overhead and leaving some slack for other devices, 4 would be a good max of dongles/adapters.

7

Agree with this.

8

You’re forgetting about upload… If you count both directions, two dongles max, leaving the rest for overhead.

2 Likes
9

could be more if off cpu and chipset

10

Right I forgot about that thank you for correcting me :slight_smile:

1 Like
11

Oh wow, honestly I had never heard of this. I just looked it up, it is exactly what I am looking for.

12

I’ll inspect the chipset on my computer and see how its architected, I am not too hopeful though since it’s a sff desktop.

13

PCIe v3.x, and one lane, I have 3 open 1 lane slots, however, I was also looking at since there’s an amd gpu in the 16 lane slot that I do not use, I could go with a beefier NIC. But I would prefer not to buy another switch, and I also am not at the point where I want to invest in 10 gigabit networking hardware… yet.