Axi dma peformance with different frequencies

Hello everyone,

I have done some test with an axi dma loopback on KR260 and encountered different latencies at 250MHz and 300MHz clock frequencies. Ideally with 300MHz the latency should be lower but it happens the opposite, with 250 MHz the system is faster just some microseconds but if start adding more modules it can be noticeable.

  • 250 MHz 683 us / 884us (Cacheable)
  • 300 MHz 775 us / 959 us (Cacheable)

The frequency limit of dma is 333MHz, I am wondering why the system is slower with high frequencies.
Is there an explanation for this?

I listed here the specs of the system, the notebook and the design.


  • Kria KR260
  • Os Ubuntu 22.04
  • Pynq 3.0.1

300 MHz:


Block design:

DmaTest.ipynb (511.5 KB)

I can also provide the bitfiles.
Kind Regards,