10Gb TCP errors on transmit?

[Visseroth]

So I noticed the new service, at least new to me, "NetStats" and was looking at things and noticed when sending a file from my server to my desktop I get TCP errors. The server is connected at 10Gb via a Chelsio x520 (if I remember the model number correctly) with a Chelsio fiber module to a Intel fiber module in my LB4M switch, the desktop at 1GB (at least for now).
I tried swapping cables, making sure there were no sharp turns, blowing out the lenses with a can of air, swapping modules with some spares. No changes.
Maybe it's normal to get TCP errors but I know TCP errors means slower speeds.
Anyone have any thoughts as to why?...

 

[Arwen]

You may want to see if your Ethernet flow control is set to symetric on both sides, server and client.

Basically a 1Gbps client can't receive beyond it's rated speed. So flow control is used to pause transmission when the receive buffer is full. TCP can compensate for lost packets, thus many people don't notice the problem.

Some 1Gbps and below Ethernet ports or drivers don't support flow control, or support it properly. But in the 10Gbps world, all port almost certainly support it properly, (it's a requirement of the standard).