Low Ethernet Throughput (200 Mbps) on ZynqMP RFSoC4x2 with PYNQ - Is this a known limitation?

Support
1

Hi everyone,

I am running the latest PYNQ image (3.1.1) on RFSoC4x2 board, and I am struggling to achieve line-rate (1 Gbps) Ethernet performance.

Currently, when running iperf3, I am consistently capped at approximately 200–250 Mbps.

Hardware Verification: I have ruled out simple hardware faults. I have tested this setup with:

  • Two different RFSoC4x2 boards (behavior is identical on both).
  • Multiple Host Machines (Ubuntu Laptop, USRP, Nvidia Jetson).
  • Multiple different Ethernet cables (Cat6).

The result is always the same: a hard cap around 200 Mbps.

Background: Before switching to PYNQ, I spent a significant amount of time debugging this on a standard PetaLinux build. I tried various configurations but could never break past this ~250 Mbps bottleneck. I documented those attempts in my thread on the AMD Forums here.

My Question to the PYNQ Team: Is this low PS Ethernet throughput a known issue or limitation with the current ZynqMP PYNQ images?

  • Have you observed this ~200 Mbps cap in your own internal testing?
  • Is it possible that I am the only one facing this, or is there a standard configuration step I am missing to unlock full Gigabit speeds?

Any insight would be appreciated.

Hardware Details:

  • Board: RFSoC4x2
  • Current Speed: ~200-250 Mbps (iperf3)
  • Target Speed: ~900-950 Mbps

Thanks!

2

Hi @Gergo_Kovacs

Thanks for reaching out. We are aware of this issue, but have not determined a root cause yet.

Thank you for sharing the forum post, that is very helpful.