Package: linux-image-6.12 Version: 6.12.x (Debian 13) Severity: important Subject: Severely reduced network speed on Debian 13 compared to Debian 12
On Debian 13 (kernel 6.12), Ethernet speed is limited to around 25 Mbps on a Realtek RTL8168e NIC. On the same machine running Debian 12, the speed consistently reaches 100 Mbps or more. The firmware `rtl8168e-3.fw` is present and correctly loaded. The driver in use is `r8169`. The issue also occurs in live sessions. Steps to reproduce: 1. Boot Debian 13 on a machine with RTL8168e 2. Check negotiated speed with `ethtool eth0` 3. Run a speed test Expected result: Network speed matching the NIC's capabilities (up to 1000 Mbps) Actual result: Speed limited to around 25 Mbps Additional information: - Firmware package `firmware-realtek` is installed - Kernel version: 6.12.x - NIC: Realtek RTL8168e - Debian 12 on the same hardware performs correctly - The issue is reproducible even with custom live ISOs Thank you for your attention, Andrea
