Basically, if a NIC doesn't explicitly say it supports those lower speeds, assume it doesn't until proven otherwise.Thanks for clarifying my question.
I had some doubt about Mellanox old CX2 and CX3 card can supports new standard 2.5Gb + 5Gb speed.
I am thinking buying this super cheap 2.5bp + 10Gbp switches, introduced by Patrick:
NEW Sub $69 Fanless 2.5GbE Switches with 10GbE
Just 1 more question, does the DAC cable works on the 10Gbp switch ports?
There are some special SFP+ transceivers that can add that support by negotiating 10Gb to the switch and the lower speed to the other device and then rate limiting the traffic themselves, but not having to use them is better.A DAC should work, but as mentioned in that video, some of the models may have grounding issues (the Vimin). My Hasivo switch using the older 2 chip switch platform also turned out to have issues with my 2 meter DAC but worked with my 0.5 meter DAC, so it is never a guarantee with these cheaper switches. I would simply ask in the other thread about these switches whether people have used them with DACs or not.