10Gtek® 25G SFP+ DAC Cable 0.5-Meter(1.65ft), 25GBASE-CR SFP28 to SFP28 Passive Direct Attach Copper Twinax Cable for Cisco, Ubiquiti, Mikrotik and Open Switches

Does what is asked

I needed to directly connect some Mellanox cards for VSAN (so no switch) with SFP28 at 25Gbe - thus DAC is the best way. I opted for 1m where perhaps even 50cm would do (servers on top of each other) but perhaps in the future will use them for something else, etc. They seem Ok and do work Ok - Mellanox works pretty much with anything in fairness, even a wire might have worked - but even at the price they don't seem quite that great. If I was using Intel then I doubt things would have gone well, they are quite picky not just with transceivers but also DAC [cables]. One cable was Ok (connectors same face up) but the other had them at 180 angle (so one facing down) - thus it required twisting to plug into the 2nd card. Obviously you're not supposed to twist it - as they remind you on packaging! I would have exchange it - but suddenly no more 1m cables in stock? Strange. Also cable is not moulded onto the connectors - like say on branded cables, so if you do twist it likely it will break internal connection. Especially at short lenghts (up to 3m) using AWG30 (thus thin) the cable is really thin and delicate. Perhaps I should have gone with longer, e.g. 3m version has AWG26 version that costs more but is more durable (and also lower resistance) but this should not be needed. They are cheap though, although other similar vendors (not brands) are the same cost. Branded cables (e.g. Dell) are about 2x-3x more expensive but perhaps worth it problematic cards, e.g. Intel. Will keep an eye for branded DAC cables and perhaps return these as I am not 100% sure of reliability, but they do work if you don't have better options and don't want to turn to random used bought on online auction sites.