SDK • SHA256 example on Pico2 RISCV takes longer with DMA

I tried running the Pico Examples hello_sha256, on a Pico 2W, in RISCV mode
The takes longer when DMA is enabled than without DMA:

Time for sha256 of 1M bytes without DMA 27ms
Time for sha256 of 1M bytes with DMA 32ms

I was expecting the opposite, based on the high level API:

use_dma Set to true to use DMA internally to copy data to hardware. This is quicker at the expense of hardware DMA resources

toolchain: RISCV_ZCB_RPI_2_1_1_3
sdk: 2.0.0
Pico2 W in RISCV mode
example version: freshly cloned by Pico VSCode Extension

Statistics: Posted by jancumps — Thu Sep 04, 2025 8:29 pm

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