For NIC issues, here is a typical checklist:
- Make sure the NICs are on the vSphere VCG
- Not only make sure that Firmware and Drivers are up to date (latest), BUT also that there are no mismatches
- Mismatches between these two have been know to cause some issues, in particular packet drops, based on my experience
- For the X710 (X71x & 72x) disabling LRO / TSO have resolved a lot of the issues encountered in the past.