Report Offensive Message
Not always the NIC
If you find a Packet sniffer shows there are network issues it's not necessarily the NIC. Try a different ethernet port first and a different cable. Try a different NIC (if you have more than one) or computer from that port. Check that your Network driver is up to date. Check that the ethernet port is patched properly (re-krone if necessary). If all this fails maybe then look at replacing hardware like the NIC.