Test the adapter across different physical USB ports, prioritizing native ports directly on the motherboard over unpowered external hubs.
Most GZCYC adapters use budget-tier controllers that prioritize cost over speed. You can verify your specific model in under Hardware IDs : gzcyc usb to lan driver
Experiencing speeds capped strictly at 100 Mbps on a gigabit-rated GZCYC adapter points to a negotiation bottleneck. Test the adapter across different physical USB ports,
Yes, if downloaded from Realtek or the official GZCYC link. Avoid “driver booster” software. gzcyc usb to lan driver
