Slower Internet Downloads Speeds Through Peplink 580

I have a Peplink Balance 580(6.1.2 build 3071). I have 1 ISP connected to WAN 1. My provisioned speeds are 105Mbps Down, 20Mbps Up.

In the following configuration I receive my contracted speeds:

  • Motorola SB6121
  • Connected to WAN1 on Balance 580
  • Unmanaged Linksys switch connected to LAN port on Balance 580
    - Both Wired and Wireless Clients demonstrate internet speeds ranging from 75-120Mbps Down and 20Mbps Up.

In the following configuration I receive slower speeds:

  • Motorola SB6121
  • Connected to WAN1 on Balance 580.
  • WAN1 configured 1000Mbps Full Duplex
  • Cisco SG300-10MP connected to LAN on Balance 580. Cisco port and Peplink port configured to 1000Mbps Full Duplex.
    • In this configuration some clients receive proper speeds, while others do not. Poor speeds are usually in the 3-10Mbps range for Download and I receive full Upload speeds.

I am specifically experiencing this issue on my equipment, but have seen the same problem on at least 12 other Peplinks configured at client sites.

Any help or suggestions are welcome.


It looks little bit strange here, as it only affected certain clients.

Have you try to apply the Balance 580 with default WAN and LAN port settings when connected to Cisco SG300-10MP switch, leave it with auto-negotiation?

As you described, are those clients experiencing poor speed always the same group of users?

Thanks and regards.

I have seen the same on my Balance 20

Comcast - Balance 20 =
Comcast - ASUS TM1900 =

Hi rebelleader. Is there any chance that the Cisco SG300-10MP has QoS or CoS rules in place that might be restricting bandwidth on some ports?
It might be worth factory resetting it so clear out any unknowns. The fact that the B580 with an unmanaged switch on its LAN gives expected performace suggests the blame lies with the CISCO switch config.

Fresno - such wildly different bandwidth throughput results need further investigation. The B20 is rated for 100Mbps throughput, although that figure is based on Ethernet frame sizes of 1280 or 1518 bytes. Actual performance can naturally vary depending on actual network traffic - but that amount of variance is very unusual. Please log a ticket with engineering here so we can investigate its cause.