How to specify a used ConnectX adapter correctly
- The suffix is the model. MCX516A-CCAT and MCX516A-CDAT are the same silicon on different PCIe generations; the suffix decides bandwidth and slot fit.
- Port type and count. SFP28, QSFP28 and QSFP56 are different cages; confirm the optic family you already standardise on.
- Height and bracket. Low-profile and full-height brackets are model specific; state your chassis type when requesting a quote.
- Firmware and boot support. Confirm the installed firmware version and whether PXE, UEFI boot or RoCE features you depend on are enabled.
- Airflow and cooling. High-speed adapters run hot in 1U chassis; confirm the airflow direction your server expects.
Used Mellanox ConnectX adapters listed on zhongxindata.hk
Availability is confirmed per part number.
| Model | Key spec | Listing |
|---|---|---|
| Mellanox ConnectX-5 MCX516A-CCAT | 100GbE dual-port QSFP28, PCIe 3.0 x16 | Mellanox ConnectX-5 MCX516A-CCAT |
| Mellanox ConnectX-5 MCX512A-ACUT | 25GbE dual-port SFP28 | Mellanox ConnectX-5 MCX512A-ACUT |
| Mellanox ConnectX-6 MCX653105A-ECAT | 100GbE single-port QSFP56, PCIe 4.0 | Mellanox ConnectX-6 MCX653105A-ECAT |
| Mellanox ConnectX-6 MCX653106A-ECAT | 100GbE dual-port QSFP56, PCIe 4.0 | Mellanox ConnectX-6 MCX653106A-ECAT |
| Mellanox ConnectX-6 MCX653105A-HDAT | 200GbE single-port QSFP56 | Mellanox ConnectX-6 MCX653105A-HDAT |
| Mellanox ConnectX-4 MCX4131A-GCAT | 40GbE single-port QSFP | Mellanox ConnectX-4 MCX4131A-GCAT |
What to check before you buy a used adapter
- Slot budget. Dual-port 100G adapters typically need x16 slots; confirm your riser configuration before committing to a model.
- Cable and optic compatibility. QSFP28 and QSFP56 cages accept different optic families; send your cable list and we confirm the match.
- Protocol support. The same adapter can be used for Ethernet or InfiniBand depending on model and firmware; confirm which mode your design requires.
- Server compatibility. Bracket height, airflow direction and firmware version decide whether the card reports correctly in your platform.
- Volume consistency. For cluster builds, confirm the batch ships with matching firmware so nodes behave identically.
How ordering works
- Send the adapter model, quantity and your server or switch model on WhatsApp +86 13068616914.
- You receive a quote per part number, stating port type, bracket and PCIe generation.
- We confirm optic, cable and firmware compatibility against your plan before the order is finalised.
- Adapters are dispatched from Hong Kong, China with export documents included.
Related catalog
Get a wholesale quote
Message our B2B team on WhatsApp +86 13068616914 with the part numbers and quantities you need. Quotes are issued per part number and are valid the day they are issued.
Request a Quote on WhatsApp +86 13068616914
Adapters we supply by speed class
- 25GbE on ConnectX-4 and ConnectX-5 for storage, management and homelab-class builds
- 100GbE on ConnectX-5 and ConnectX-6, the mainstream data center rate
- 200GbE on ConnectX-6 variants, for GPU training fabrics and storage arrays that can saturate 100G on both ends
Confirming the card fits your server and your cabling
- Match the variant suffix to the media type, the bracket and the card height your chassis accepts
- Check the PCIe lane budget — a dual-port card consumes more lanes and may need a full-width slot
- QSFP28 for 100GbE and QSFP56 for 200GbE, so the optic type follows the speed class
How we test every adapter before it is listed
- Cleaned, re-flashed and bench-tested on our own test line
- Part number, port count, negotiated link rate and firmware level recorded per unit
- Error counters read, so a card that links but produces errors does not get listed
Why buyers choose used adapters
- Network adapters are among the most testable components, which makes the secondary market a low-risk fit
- The cost difference is widest on the previous generation, which is where most expansions land
- The condition of each unit is stated in the quote and the firmware level is confirmed per unit
Related reading
- MCX516A-CCAT 100GbE adapter — the mainstream model
- MCX512A 25GbE adapter — the entry speed class
- ConnectX NIC buyer guide — the selection detail
- Network adapters — category hub
Frequently Asked Questions
Which Mellanox ConnectX adapters do you supply?
We stock ConnectX-4, ConnectX-5 and ConnectX-6 variants at 25GbE, 100GbE and 200GbE, and other models are quoted per part number. Send the model and the quantity and we will confirm what we can allocate, with the condition of each unit stated in the quote.
How do I know which ConnectX variant fits my server?
Three things decide it: the bracket and card height your chassis accepts, the media type your cabling uses, and the PCIe lanes you can spare. Send the server model and the switch model and we will confirm the exact variant, which is the easiest way to avoid a fitment problem on arrival.
Can a 25GbE adapter connect to a 100GbE switch?
Yes, where the switch supports breakout. A 100GbE switch with QSFP28 cages can present a 25GbE link and the adapter negotiates down, which is the standard way to stage a migration to 100GbE uplinks without buying 25GbE access switches.
Do used Mellanox adapters accept firmware updates?
Most do, but some adapters only accept a specific firmware progression and will not jump directly to the newest release. Moving through the intermediate image in order resolves it. We re-flash during testing and state the level each unit ships with, so you know the starting point.
How do you verify a used Mellanox adapter?
We clean, re-flash and bench-test on our own test line, then confirm the part number, port count, negotiated link rate and firmware level, and we read the error counters. A card that links but produces errors does not get listed. Ask for photos of the exact unit and its firmware level before you commit.
What warranty comes with a used adapter?
90-day warranty from delivery, on a unit cleaned, re-flashed and bench-tested on our own test line. The condition of each unit is stated in the quote, and batch pricing applies to volume orders.