Superior Ethernet Performance Test for Raspberry Pi RP2040
Comparing the network performance test between W5100S and LAN8720.


WIZnet can offer a simple way to add Ethernet connectivity via hardwired TCP/IP

since there is no network (TCP/IP) processing block in RP2040.


We conducted a performance test to compare W5100S and LAN8720,

as LAN8720 was mentioned in Raspberry Pi’s blog, “How to add Ethernet to Raspberry Pi Pico – Raspberry Pi.” >


Test Environment and Procedure

Test Block Diagram


  1. Establish Network connection between PC and Raspberry Pi RP2040
    (PC Server mode <-> RP2040 Client mode)
  2. Receive the data sent from PC, and copy to memory on RP2040
  3. Send back copied data from RP2040 to PC
  4. At this point, measure 10 times Send/Recv speed using AX1 program (network performance measurement tool)

Test environment

Test Result & Analysis

As shown in the test environment table,

link speed was limited to 10Mbps because LAN8720 RMII reference clock speed was set to 50Mhz,

as mentioned in the blog post, “How to add Ethernet to Raspberry Pi Pico – Raspberry Pi.”


Please refer to the below paragraph from the blog.


  • Using W5100S with RP2040 @133MHz, SPI 33MHz,

Link Speed/10Mbps average performance was 2.39Mbps after 10 cycles Send/Recv

  • Using LAN8720 with RP2040@133MHz, RMII 50MHz,

Link Speed/10Mbps average performance was 0.322Mbps after 10 cycles Send/Recv



  • W5100S network performance measurement at Link Speed/100Mbps

Using W5100S with RP2040 @133MHz, SPI 33MHz,

Link Speed/100Mbps average performance was 10.89Mbps after 10 cycles Send/Recv



Please note that WIZnet can open all codes and utilities used for this network performance test.

Contact Jake in case you have any suggestions on how to improve the tests or performance.

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