Raspberry Pi boosts Pi 5 performance with SDRAM tuning

Original Article ↗ Hacker News Discussion ↗

Pi 5 SDRAM Tuning & Performance Gains

  • Several commenters report ~10% speedups in real workloads (e.g., local LLM inference) from the SDRAM tuning.
  • Tweaks also benefit Pi 4 and are likely already enabled on upcoming boards like the Pi 500.
  • Some want clearer, consolidated benchmarks that combine SDRAM tuning, “fake NUMA” configuration, and ARM-specific quantization changes for LLMs.

Pi vs Intel N100 and Other x86 Mini PCs

  • Many argue an Intel N100 mini PC now offers much better performance per dollar and similar or slightly higher power use, especially once you factor in Pi cases, power supplies, SD/SSD, and cooling.
  • Counterpoint: in some regions N100 boxes cost 2–3× a Pi 5; once VAT, shipping, and shortages are considered, Pi often remains cheaper.
  • x86 boxes are praised for RAM capacity (16–32 GB), storage options (native NVMe/SATA), PCIe I/O, and strong mainline Linux support.

Power, Cooling, and Noise

  • Pi 5: reported idle around 3.5–5 W with passive cooling; with good aluminum cases, can run cool and silent under load.
  • N100: idle/work power figures vary (some see ~6–10 W), often needs active cooling; fans and dust are recurring concerns, though fanless designs exist and underclocking/undervolting can help.
  • For battery/solar or “tuck-away” silent servers, many still prefer Pi.

Use Cases: GPIO, Education, Embedded vs Desktop

  • Pi’s major advantages cited: GPIO header, camera connector, HAT ecosystem, long-term availability, educational focus, custom Debian-based desktop, and strong documentation.
  • Some say Pi is overkill for GPIO compared to cheap microcontrollers; others emphasize the unique niche of “full Linux + GPIO” on one small board.
  • For general-purpose desktops, home media, and servers, many recommend used/refurb x86 minis or laptops instead.

SBC Alternatives and Software Support

  • Rockchip/Orange Pi/NanoPi and ODROID boards are cheaper or more powerful on paper, but often rely on vendor BSP kernels or community-maintained distros with patchy support.
  • Pi is seen as more consistent and better documented, which justifies its price for many.

Technical Memory/NUMA Discussion

  • “Fake NUMA” on Pi 4/5 is used to improve SDRAM bank utilization and allocation patterns.
  • SDRAM refresh-rate tuning based on temperature can reduce refresh overhead; some wonder about PC support and potential rowhammer implications, which remain unclear in the thread.