Aliexpress has a 4 port 2.5gbit switch with 2*SFP+ sockets for $34.35 delivered [1]. 4 ports isn’t very good for the more common use cases (if daisy chaining them then it’s only
2 available for devices) so this is really a device for use with 10Gbit uplink.
Aliexpress has a pair of SFP+ 10Gbit devices with 1M of copper between them for $15.79 delivered [2]. That page also offers a pair of QSFP+ 40Gbit devices with 1M of copper between them for $27.79 delivered.
So you can get a 2.5gbit switch with two 10gbit uplink cables to nearby servers for $66.86 including postage. I don’t need this but it is tempting. I spent $93.78 to get 2.5gbit networking [4] so spending $66.86 to get part of my network to 10gbit isn’t much.
It is $99.81 including postage for a Mellanox 2*40Gbit QSFP+ card and two QSFP+ adaptors with 3M of copper between them [5]. It is $55.81 including postage for the Mellanox card without the cable. So that’s $155.62 for a point to point 40gbit link between systems that are less than 3M apart, that’s affordable for a home lab. As an aside the only NVMe I’ve tested which can deliver such speeds was in a Thinkpad and the Thinkpad entered a thermal throttling state after a few seconds of doing that.
The best price I could see for a 40Gbit switch is $1280 for a L3 Managed switch with 2*40G QSFP+ slot ports, 4*10G SFP+ ports, and 48*2.5G RJ45 ports [6]. That’s quite affordable for the SME market but a bit expensive for home users (although I’m sure that someone on r/homelab has one).
I’m not going to get 40Gbit, that’s well above what I need and while a point to point link is quite affordable I don’t have servers in that range. But I am seriously considering 10Gbit, I get paid to do enough networking stuff that having some hands on experience with 10Gbit could be useful.
For a laptop a 5gbit ethernet USB device is $29.48 including delivery which isn’t too expensive [7]. The faster ones seem to be all Thunderbolt and well over $100, which is disappointing as USB 3.2 can do up to 20Gbit. If I start doing 10gbit over ethernet I’ll get one of those USB devices for testing.
For a single server it’s cheaper and easier to get a 4 port 2.5Gbit ethernet for $55.61 [8].
- [1] https://www.aliexpress.com/item/1005006820869547.html
- [2] https://www.aliexpress.com/item/1005007099994832.html
- [3] https://www.aliexpress.com/item/1005009741428514.html
- [4] https://etbe.coker.com.au/2024/01/19/2-5gbit-ethernet/
- [5] https://www.aliexpress.com/item/1005007257555687.html
- [6] https://www.aliexpress.com/item/1005007561221707.html
- [7] https://www.aliexpress.com/item/1005009176898872.html
- [8] https://www.aliexpress.com/item/1005007046872368.html

Unless you need the switch brand new it’s worth looking at companies, including Bargain Hardware (https://www.bargainhardware.co.uk/networking-storage/switches/40g-switches/instock), that operate in the professional refurbishment market. As for instance Bargain Hardware has 40G managed network switches starting from around £110.