Hello TP-Link team and users,

I want to document a critical issue I’ve encountered with the Deco BE65 that appears to be caused by thermal throttling, affecting both Ethernet link speed and network stability.

System Setup:

• Deco BE65 (latest firmware as of July 2025)

• Wired via 2.5G port to TP-Link ER605 router

• Ethernet cables tested and confirmed 1Gbps capable (shielded and unshielded)

• Internet access provided via dual WAN

• Environmental temp: ~30°C indoor, no direct sunlight

Observed Issues:

1. Ethernet Link Drops to 100 Mbps

   • Initial setup negotiates at 1000 Mbps

   • Within 30–90 minutes, link speed drops to 100 Mbps

   • Changing cables temporarily helps, but issue returns

   • Inserting unmanaged switch between BE65 and router restores 1 Gbps (temporarily)

   • 
      

     2.)Thermal Dependence

   • BE65 surface becomes warm to the touch after uptime

   • Adding a USB fan on top restores full 1000 Mbps link within 10–15 minutes

   • Removing fan results in degradation within hours

   • This confirms some form of thermal performance drop

   • The BE65 offers no thermal feedback, logs, or protections 

   •  

   • 3.)LAN IP Cannot Be Changed Reliably

   • Attempted to change default LAN IP from 192.168.68.1 to 192.168.3.1

   • Multiple errors encountered: subnet overlap, invalid format, gateway conflict

   • Even when unplugged from upstream network, it refuses change

   •  

   • 4.) PHY Errors + DHCP Failures

     • System logs show thousands of PHY errors

     • DHCP occasionally fails for wired clients

     • Attempting to add Deco M5 node results in “no internet” unless IP is manually set

   • What I've Tried:

   • Verified all cables (CAT6 / CAT5e with shielding)

   • Used digital cable tester

   • Replaced factory cables

   • Removed unmanaged switch

   • Isolated unit from upstream routers

   • Passive cooling (fan) = immediate link recovery

   • Factory reset and reconfigured from scratch

   • Reached out to support – response was limited to “try another cable”

   • Conclusion:

     The Deco BE65 appears to suffer from a thermal design limitation or firmware issue that causes:

   • Silent link speed degradation

   • DHCP misbehavior

   • PHY-level instability

   • And no support for user cooling or thermal control

   • I would like to know:

   • Has TP-Link acknowledged this thermal behavior internally?

   • Is a firmware fix planned for the BE65 to mitigate or monitor throttling?

   • Are other users seeing PHY errors or DHCP instability in warm environments?

   • Thanks for any input. Happy to provide logs or video if needed.