Fix Slow Network Speed on Dell Precision T3680 Running CentOS 8.5

If you own a Dell Precision T3680 workstation and have installed CentOS 8.5, you may encounter slow or unstable network performance. This issue typically arises from outdated or incompatible default drivers for the built-in Intel Ethernet and Wi-Fi adapters. In this guide, we’ll walk through identifying your network hardware, installing the latest Intel drivers, verifying compatibility, and optimizing network speeds for a reliable, high-performance connection.

1. Hardware Identification & Problem Diagnosis

First, confirm the network adapters in your Dell T3680. Most models come with:

• Wired: Intel® Ethernet Connection I219-LM (1Gbps)
• Wireless: Intel® Wi-Fi 6E AX211 (802.11ax)

Check Network Adapters

# Check wired Ethernet controller
lspci | grep -i ethernet

# Check wireless adapter
lspci | grep -i wireless

Check Current Driver & Speed

Use ethtool to view driver status and negotiated link speed:

# For wired (usually eth0 or eno1)
ethtool eth0
ethtool -i eth0 | grep driver

Common Issues

• Outdated default e1000e driver for I219-LM causes slow throughput
• CentOS 8.5 lacks firmware for AX211 (no Wi-Fi or extremely slow speeds)
• Auto-negotiation failure (stuck at 100Mbps instead of 1000Mbps)

2. Update Intel I219-LM Wired Network Driver

The I219-LM uses the e1000e driver. Upgrading to the latest version resolves stability and speed issues.

Step 1: Install Build Dependencies

sudo dnf install -y kernel-devel gcc make git

Step 2: Download & Extract the Latest Driver

wget https://downloadmirror.intel.com/9180/eng/e1000e-3.8.7.tar.gz
tar -zxvf e1000e-3.8.7.tar.gz
cd e1000e-3.8.7/src

Step 3: Compile & Install

make install
sudo modprobe -r e1000e
sudo modprobe e1000e

Step 4: Verify the New Driver

ethtool -i eth0 | grep version

3. Install Intel AX211 Wi-Fi 6E Driver & Firmware

CentOS 8.5 does not include the required iwlwifi firmware for AX211. Manual installation is necessary.

Step 1: Install Kernel Headers & Tools

sudo dnf install -y kernel-headers-$(uname -r) flex bison

Step 2: Compile iwlwifi Driver

git clone https://github.com/intel/iwlwifi.git
cd iwlwifi
make -j$(nproc)
sudo make install

Step 3: Install Required Firmware

wget https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/plain/iwlwifi-ty-59.ucode
sudo cp iwlwifi-ty-59.ucode /lib/firmware/

Step 4: Load the Driver

sudo modprobe -r iwlmvm iwlwifi
sudo modprobe iwlwifi
sudo systemctl restart NetworkManager

4. Compatibility Check & Performance Tuning

Kernel Version Check

uname -r

• I219-LM (e1000e): Works with kernel ≥ 3.10 (CentOS 8.5 default is compatible)
• AX211 (iwlwifi): Requires kernel ≥ 5.10 → Upgrade if necessary

Force Gigabit Full-Duplex

If auto-negotiation fails:

sudo ethtool -s eth0 speed 1000 duplex full autoneg off

Disable Secure Boot (If Driver Fails to Load)

sudo mokutil --disable-validation

Test Network Throughput

Use iperf3 to verify real-world speed:

sudo dnf install -y iperf3
iperf3 -c server_ip

5. Troubleshooting Common Errors

6. Official Driver Resources

• Dell Support: Enter your service tag for OEM-specific updates
• Intel Download Center:
  • Wired: e1000e driver for Intel I219-LM
  • Wireless: iwlwifi firmware for AX211

dmesg | grep -i eth
dmesg | grep -i wifi