> In my experience even saturating 25Gb links is rather easy to do when using 9000 byte MTU on mid-tier server hardware. But that's tweaking the setup already

> In my experience even saturating 25Gb links is rather easy to do when using 9000 byte MTU on mid-tier server hardware. But that's tweaking the setup already, it requires changes, testing and verification, and can cause problems in downstream equipment. And for a lot of applications, a 9K MTU will not be enough to saturate the link because they'll need NUMA awareness, or the NIC queues will need tweaking to avoid imbalances, or the application is not ready to send at that speed... I'm not saying it can't be done, of course it can. But it isn't "plug a bigger card and it'll go faster".