Early Gigabit drivers were aggressive with power saving (EEE - Energy Efficient Ethernet). This caused random "link flapping" (connection dropping for 2 seconds). Version 2.64 defaults to a more conservative power state. Your connection stays live, and you save power without the stutter.
It’s the workhorse of the motherboard world. From budget H610 boards to premium Z790 gaming rigs, if it has an Ethernet port, chances are Realtek is powering it. realtek pcie gbe family controller series v2.64
Deep Dive: The Realtek PCIe GbE Family Controller (v2.64) – Why This Driver Still Matters Early Gigabit drivers were aggressive with power saving
If you’ve ever looked inside Windows Device Manager, you’ve seen it. That unassuming entry under Network adapters : . if it has an Ethernet port