Xiaomi AX3000T: Low Download Speed - Solution

Low Incoming Speed Problem on Xiaomi AX3000T: Causes and Solutions

The problem of low incoming speed with normal outgoing speed on Xiaomi AX3000T is a common malfunction related to the peculiarities of the MediaTek processor and firmware operation. This can be caused by VLAN configuration, DSA driver issues, or limitations in incoming traffic processing, especially when using OpenWrt or after kernel updates.

Table of Contents

• What is the low incoming speed problem?
• Main causes of the problem
• Diagnosis and checking
• Solutions and troubleshooting methods
• Router settings for speed optimization
• Alternative solutions

What is the low incoming speed problem?

The problem of low incoming speed (download) with normal outgoing speed (upload) on Xiaomi AX3000T manifests as a significant decrease in download speed while maintaining good upload speed. This asymmetric network behavior indicates a specific issue with incoming traffic processing in the router.

Research shows that users report download speeds dropping from 300 Mbps (the maximum speed from the provider) to only about 20 Mbps, while upload speed remains at the previous level [source 1]. Similar symptoms are observed when connecting via both wired and Wi-Fi, indicating a systemic router issue rather than a specific interface.

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Main causes of the problem

OpenWrt firmware issues

One of the main causes is the incompatibility of various OpenWrt firmware versions with the Xiaomi AX3000T hardware. As noted in [OpenWrt forum], many users encounter this problem after updating the Linux kernel from version 6.6 to 6.12 [source 1]. In this case, it is recommended to roll back to a stable version or wait for fixes in new releases.

VLAN configuration

Many users have found that the speed issue occurs when using VLAN. Research shows that when VLAN is disabled, incoming traffic speed returns to normal levels [source 1]. This is related to the peculiarities of the MediaTek MT7531AE switch operation and tagged packet processing.

DSA (Distributed Switch Architecture) issues

Another serious cause is problems with the distributed switch architecture (DSA). As explained in [OpenWrt forum], the speed of one of the Ethernet interfaces can affect the download speed in the bridge to which Wi-Fi is connected [source 5]. This can lead to speed limitation to 10/100/1000 Mbps depending on the configuration.

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Diagnosis and checking

Before troubleshooting the problem, it is recommended to perform the following diagnosis:

1. Direct connection check

   • Connect your device directly to the provider’s modem
   • If the speed is normal, the problem is specifically with the router

2. Testing different interfaces

   • Check the speed on all LAN ports of the router
   • Compare results when connecting via Wi-Fi and cable

3. VLAN configuration check

   • Ensure that VLANs are configured correctly
   • Try temporarily disabling VLAN for testing

4. CPU load monitoring

   • Check the load on the MediaTek MT7981B processor
   • High load can limit incoming speed

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Solutions and troubleshooting methods

Firmware update or rollback

If you are using OpenWrt, try:

• Rolling back to the previous stable kernel version (6.6)
• Updating to the latest stable version with fixes
• Reinstalling the firmware via XMiR-Patcher [source 9]

Network parameter settings

1. Disabling acceleration features

   • Disable hardware acceleration in router settings
   • Try using software traffic processing

2. MTU settings

   • Set MTU value to 1500 for standard configuration
   • If necessary, try values 1492 or 1400

3. QoS optimization

   • Disable or reconfigure Quality of Service
   • Limit background processes using traffic

Network configuration

1. Changing port operation modes

   • Ensure that the WAN port is correctly identified
   • Check the switch operation mode

2. DHCP settings

   • Check DHCP ranges for overlap
   • Ensure the DHCP server is working correctly

3. Filtering and security

   • Temporarily disable firewall and filters
   • Check if incoming connections are being blocked

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Router settings for speed optimization

Wi-Fi optimization

To improve Wi-Fi speed, it is recommended:

1. Selecting the optimal channel

   • Use analyzers to choose the least congested channel
   • For 5 GHz, select channels 36, 40, 44, 48, 149, 153, 157, 161

2. Channel width settings

   • For maximum speed, use 80/160 MHz
   • In the presence of interference, limit to 40 MHz

3. Transmission power

   • Set medium or high signal power
   • Avoid maximum power for stability

Network optimizations

1. Buffer settings

   • Increase network buffer sizes
   • Configure transmission queue parameters

2. TCP optimization

   • Enable TCP window scaling
   • Configure delay parameters

3. DNS optimization

   • Use fast public DNS servers
   • Configure DNS caching

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Alternative solutions

Using the router in access point mode

If the problem is not resolved, you can use the Xiaomi AX3000T only in access point mode:

1. Disable the DHCP server on AX3000T
2. Connect the WAN port to the main router
3. Use only LAN ports and Wi-Fi

Firmware replacement

Consider alternative firmware options:

• Stock Xiaomi firmware (if you are using OpenWrt)
• Other alternative firmware supporting AX3000T

Equipment upgrade

In case of chronic problems, consider:

• Upgrading the router to a model with more modern hardware
• Using additional network equipment to offload

The problem of low incoming speed on Xiaomi AX3000T requires a comprehensive approach to diagnosis and troubleshooting. In most cases, proper VLAN configuration, firmware optimization, or changing router operation modes allow solving the problem and restoring full internet speed.

Sources

1. WiFi download speed degraded on Mediatek Filogic Xiaomi AX3000T with kernel 6.12 and VLANs, upload is fine - OpenWrt GitHub
2. Xiaomi Router AX3000 has lower speed after using it as main router - Reddit r/HomeNetworking
3. Issues with Xiaomi AX3000T router – Connection problems and troubleshooting attempts - Reddit r/homelab
4. Xiaomi ax3000t slow wifi compared to old router - Reddit r/openwrt
5. OpenWrt support for Xiaomi AX3000T - OpenWrt Forum
6. Xiaomi AX3000T + OpenWRT 24.10: Ethernet/Wi-Fi 6 Asymmetric Speed Issues - OpenWrt Forum
7. Router rebooting when downloading at full speed (Xiaomi Mi Router AX3000T) - OpenWrt Forum
8. Xiaomi AX3000T – discussion - 4PDA
9. Xiaomi AX3000T died after the final step of sysupgrade - Reddit r/openwrt
10. Slow speed on AX3000 - Reddit r/Xiaomi