Dell CS24-TY NIC disconnection issues

Hi

I have an CS24-SC and a CS24-TY . Both are with Windows 2012 R2.

From some time I have an annoying issue with my CS24-TY (that act as AD/DNS and as Webserver). The network adapter (dual Intel 82576 Ethernet controller on-board) is configured in Windows in NIC team (at a time for testing purpose I was also removed the team, and l let NIC's as individual ports, but also it does not change the behavior).

I noticed that in a random manner (but I observed that is maybe triggered when is somehow a peak in traffic) Windows report that media is disconnected and the only way to exit this condition is to reboot my server. After this is ok again for periods that may last from days, to minutes.

As infrastructure I have some regular GB switches (not smart, regular ones, I even changes them since I observed this issue). I have tried several changes about NIC properties (disable offload etc.) and about NIC teaming properties, but I can't say that I noticed an improvement. Anyway I have logical reasons to think that is not a hardware failure of NIC since after restart it comes working again (but maybe is a wrong assumption). I may buy an PCI-e dual port NIC, but since are not cheap I want to be sure that I do the wright choice. I still believe that it may be a miss-configuration. On the other hand the other server that is fairly similar, works perfect. I try to replicate it's network configuration on this faulty one, but it solves nothing.

This is annoying because I used for years regular, cheap, desktop machines as Windows Servers and is for the first time to encounter this nasty failure.

Anyone can have a hint?

Best regards