Been racking my brain trying to figure out why the Realtek 5g is being throttled to 30mbps or less while the Intel 2.5g runs buttery smooth to it's isp rated speeds of 1000mbps. My setup is as follows:
995X3D + Crosshair Hero x870e + RTX 3090 + Unifi Dream Router + 1200w SuperFlower PSU + 96GB G.Skill RAM
Here's everything I've tried:
- Downloaded the latest Realtek PCIe 5 GbE driver directly from Realtek’s official site And ASUS.
- Same ethernet cable works fine on the Intel Lan Controller, so shouldn't be an issue on Realtek right?
- Uninstalled completely from device manager and ran default Windows 11 drivers.
- Installed the driver manually (after verifying INF match) to ensure proper RTL8126 support.
- Tested for network connectivity, link stability, and 5 Gb throughput under load.
- Confirmed Windows 11 x64, BIOS, chipset, and LAN firmware are fully up-to-date.
Monitored performance and system stability post-install to verify no driver conflicts
Toggled these settings on and off:
Setting Recommended value
| Energy Efficient Ethernet / Green Ethernet | Disabled |
| Power Saving Mode / Smart Power Down | Disabled |
| Flow Control | Disabled (test both later) |
| Interrupt Moderation | Disabled |
| Large Send Offload v2 (IPv4/IPv6) | Disabled |
| Receive Side Scaling | Enabled |
| Jumbo Frame | Disabled / 1500 bytes |
I'm sure there are other things I neglected to mention which I have already tried but I've given up at this point because everything else on this board functions smoothly except Realtek adapter. So I'm all ears if anyone has a solution.
