Written 22 Aug 2026. Specs from the maker pages linked below. Prices from those stores. I haven't used these.
New 10G SFP+ NIC vs staying on 2.5G copper
Don't buy 10G until a single flow fills 2.5. When it does, a new 10Gtek 82599 dual-SFP+ card plus a 2 m DAC is the retail path, not an eBay “pulled X520.”
If the other end is still a normal ethernet jack, the TP-Link TX401 (10G over copper, ships with Cat6A) is the copper path. That is a later note. Stay on the TX201 and a 2.5G switch until one flow is actually full. The DAC is here.
What to buy
| Card | What it is | Street, 22 Aug 2026 | Buy if |
|---|---|---|---|
| TP-Link TX201 | PCIe 2.5G copper. ASIN B0BG685PKM. | About $27 (Amazon snippet $26.99; see the USB vs PCIe note). | A single flow is not filling 2.5. This is still the default NIC. |
| 10Gtek dual SFP+ (Intel 82599ES) | X520-DA2 equivalent, new, not pulled. ASIN B01DCZCA3O. Linux ixgbe. Does not do 2.5/5G. Needs SFP+ DAC or optic. 10Gtek catalog: X520-10G-2S-X8 = X520-DA2 equivalent. | Amazon $51.99. | One flow fills 2.5 and both ends have (or will have) SFP+ cages. |
| TP-Link TX401 | 10GBASE-T. ASIN B08D71PVXG. PCIe 3.0, low-profile bracket in box, 1.5 m Cat6A included. Back-compat 10/5/2.5/1G. | Amazon snippets $64.50 and $89.99 (sold by Amazon on the $89.99 capture). | The other end is still RJ45. Later buy. Not a switch. |
Skip
Skip used eBay Intel X520 / X710 pulls. No stable ASIN. Skip buying 10G because the card is $52. Skip treating this card as a 2.5/5G copper NIC. It is not.
Sources
Amazon 10Gtek B01DCZCA3O ($51.99). Amazon TX201. Amazon TX401. 10Gtek NIC catalog. ComputingForGeeks 10GbE-for-Proxmox (ixgbe vs i40e). SpeedTestHQ 2.5G vs 10G 2026.