Intel X550 10G negotiation issues with cisco chips

[hypervisor]

Hi folks,

I recently faced serious connectivity issues with X11SSZ-TLN4F-O and X10SDV-TLN4F boards connected to a ZyXEL XS1920-12 switch.

Most of the time the port negociate at 1G but in very few cases it negociate at 10Go.
I'm not alone in this situation since a friend was unable to get his X10SDV-4C-7TP4F board working in 10G with a SG500X switch.
BTW, one supermicro engineer seems to already have some clues about it: Intel X550-T2 Card not compatible to HP 1950-24G-2SFP+-2XGT-PoE+ Switch

Did you guys have feedback with other switches?

 

[aero]

To put it eloquently, this is just one of several reasons why 10Gbase-T flat out sucks.

Here's a similar issue reported by another STH user with Netgear switches.

A warning for people looking at Netgear 10G gear