Raspberry Pi CM5 is a faster, drop-in upgrade

Original Article ↗ Hacker News Discussion ↗

Carrier Boards, NAS, and Hardware Choices

  • Multiple suggestions for CM-based NAS carrier boards: Axzez Interceptor and Radxa Taco (though Taco availability and heat/power efficiency are concerns).
  • Some users prefer skipping SBC NAS entirely in favor of small x86 boxes (ThinkCentre Tiny, N100/N150 ITX boards) plus external enclosures, citing better power and less cabling chaos.
  • USB3 multi-bay HDD enclosures are debated: some warn they’re “bad,” others report years of trouble‑free ZFS use with cheap 4‑bay boxes.
  • PCIe in small PCs can be repurposed (e.g., for extra NICs or storage), but often requires proprietary risers and sacrifices internal bays.

Pi CM in Commercial Products & Suitability

  • Compute Modules appear in commercial devices (synths, music gear, 3D printers). Many run customized Linux with userland UI on top.
  • Opinions split on using CM4/CM5 in products:
    • Pro: Long availability (8–12 years), combined volume lowers component cost, good software stack, modular FCC compliance saves certification money.
    • Con: Scarcity during shortages burned some teams; one user refuses to use Pis in retail products again. Connector reliability vs soldered SoM is a concern for some.
    • Guidance: CM is reasonable up to roughly 10k/year volumes; above that, custom designs may become cost‑effective.

Kernel, Ecosystem, and Support

  • Pi’s kernel is a maintained fork of mainline Linux; patches are regularly upstreamed and tracked near current versions.
  • Some value Pi for strong community support and relatively smooth mainline compatibility vs other ARM boards.
  • Others complain that non-Pi distros can still be painful, and that running truly vanilla kernels with fully open drivers remains a goal rather than reality.

Performance, I/O, and Boot

  • Users note large real‑world speed gains from CM5 and Pi 5, especially USB3 and PCIe vs older models.
  • Boot time of ~23 seconds is seen as improvable via trimming systemd units or using lightweight images.
  • SD card I/O on Pi 4 is widely criticized. A2‑class cards and especially USB3 SSDs are reported to dramatically improve responsiveness.
  • Suggestions include preload, F2FS, and tuning/overclocking SD bus, but external SSDs are generally considered the real fix.

Video Encode/Decode Changes

  • CM5’s SoC provides hardware H.265 decode but no hardware encode; encoding is CPU‑only.
  • Some argue Pi 5 CPU improvements can outperform Pi 4’s hardware encoder in speed/quality if power isn’t constrained.
  • Others see this as a regression for low‑power or dedicated encode use cases.

Alternative SoMs and Boards (Radxa, Rockchip, OrangePi)

  • Radxa CM5 with RK3588S2 is mentioned as significantly faster than Pi CM5 at slightly higher price and offering an NPU useful for ML/LLM workloads.
  • Trade‑off emphasized: better raw specs vs weaker ecosystem and support.
  • Other Rockchip/OrangePi boards can outperform Pi 5 in CPU, RAM, and accelerators, but users report kernel, driver, and long‑term support as “barely there” or fragile.

Home Assistant Yellow and CM5/Alternatives

  • CM5 support for Home Assistant Yellow has been announced.
  • Interest in running Yellow with Radxa CM5 and mainline kernels exists, but no clear success reports; compatibility is described as uncertain and risky for a live home setup.

Form Factor, Pricing, and Use Cases

  • Debate over “credit-card sized” marketing; dimensions match roughly in two axes, but thickness makes “volume” comparison pedantic.
  • Some feel Pi pricing has drifted into low‑end x86 territory; others counter that Pi’s value is more in support than raw specs.
  • The original $5 Zero is remembered as effectively unavailable; Zero 2W at $15 is seen as more usable but no longer in “impulse buy” territory.
  • CM5 performance is compared to decade‑old laptop CPUs; people are surprised there isn’t a popular CM‑based upgradable laptop shell, but note it’s hard to beat used x86 laptops.