Selection Guide

Choosing a Rockchip SoM: a decision table

Most Rockchip selection mistakes are made in the first ten minutes — someone picks the fastest part on the list before the product's real constraints are written down. This note is the order we use: constraints first, silicon second, with the platform matrix we ship against.

Bestom engineering note — written by our own design and BSP engineers from work on Rockchip platforms. Platform parameters quoted here are taken from our published datasheets; see Core Boards & SoM. For translated community notes, see the Tech Notes index.

Step 1

Write the constraints down, in this order

Each line eliminates platforms. Do them in order — the cheap ones first.

#ConstraintWhat it eliminatesWhere it bites if you skip it
1Operating temperature rangeAnything rated commercial when you need industrialThermal re-design after the enclosure is tooled
2Mechanical envelope (board size, connector height, mounting)BTB boards in a 16 mm-thick product; 55×75 mm boards in a handheldLate change of connector type → new carrier board
3Display path (MIPI-DSI / LVDS / eDP / HDMI, lanes, resolution)SoCs whose display controller does not reach your resolutionFrame-rate ceiling discovered at bring-up
4Camera / vision path (MIPI-CSI lanes, ISP requirement, number of streams)Parts without an ISP when you need 3A / HDR / 3DNRYou buy an external ISP you did not budget
5NPU need — and whether it is real (see Step 2)Choosing a 6 TOPS part for a 0.3 TOPS taskOver-spec BOM, higher power, longer thermal design
6OS / software stack (Android, Linux, Buildroot/Yocto, RTOS)Android-only platforms when you ship Linux, and vice versaBSP re-port, or an OS you cannot maintain
7Supply horizon (how long the product must stay in production)Parts with a short market life relative to your product lifeLast-time-buy or a forced re-design

The rule we use: if steps 1–4 do not already reduce the list to two or three parts, the requirements are not specific enough yet — and no amount of TOPS comparison will fix that.

Step 2

"We need AI" is not a constraint

Ask these four questions before any NPU number enters the discussion.

Is the model fixed, or will it change?

A frozen model can be quantised once and validated once. A model that gets retrained every quarter needs a deployment and calibration pipeline, not just TOPS.

What is the per-frame budget?

State it as frame rate × resolution × latency ceiling. "Real-time" is not a spec; 25 fps at 1080p with a 100 ms ceiling is.

Where does the data go?

On-device inference, gateway inference and cloud inference produce completely different platform choices. Decide this before the silicon.

Who owns accuracy after quantisation?

INT8 quantisation is where most schedule slips hide. If nobody owns the accuracy budget, the model will not land on the NPU on time.

A common, honest answer to these four questions is "no NPU needed". A Cortex-A class SoC with a GPU and a good ISP solves a surprising share of vision products. Choosing a lower tier here is usually the higher-quality engineering decision.

Step 3

The platform matrix we ship against

Bestom core boards and SoMs, as published in our datasheets. Use it to size the shortlist — not to pick the winner.

ModelSoCCPUNPUGradeMechanicalOS
M88RK35884×A76 + 4×A55 @2.6GHz6 TOPS INT4/8/16 · FP16/BF16/TF32industrialBTB 320pin · 55×75×8mmAndroid / Linux
M76RK35764×A72 + 4×A536 TOPS dual-corecommercialBTB connectorAndroid
M68RK35684×A55 @2.0GHz0.8 TOPS (RKNN)commercialBTB 240pin · 56×50mm · 0~65℃Android / Linux
M66RK35664×A55 @1.8GHz1 TOPSindustrial · −20~60℃stamp hole 144pin · 45×45mmAndroid / Linux
B66RK35664×A55 @1.8GHz1 TOPScommercial · −20~60℃whole board 70×110mm (SBC, no carrier needed)Android 11
M506RK3506G23×A7 + M0 @1.5GHznone — audio/HMI dedicatedcommercialhalf-hole 6-layerBuildroot / Yocto
M08DRK2108DHiFi3 DSP + Cortex-M4Fnone — audio/voice dedicatedcommercialstamp hole 60 pad · 16×16mmRT-Thread

Read the matrix as a funnel. M88 vs M76 is a CPU/GPU class decision, not an NPU one — both are 6 TOPS. M68 vs M66 is a temperature-grade and mechanical decision. M506 and M08D are not "smaller versions" of the above: they are dedicated platforms whose value is not having a general-purpose SoC in the BOM at all.

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