http://wiki.radxa.com/Rockpi4/getting_started#
https://www.cnx-software.com/2018/11/08/rock-pi-4-raspberry-pi-rk3399-board/

SoC – Rockchip RK3399 big.LITTLE hexa-core processor with  2x Arm Cortex-A72 @ up to 1.8 GHz, 4x Cortex-A53 @ up to 1.4 GHz, a Mali-T864 GPU with support OpenGL ES1.1/2.0/3.0/3.1, OpenVG1.1, OpenCL, DX11, and AFBC, and a VPU with 4K VP9 and 4K 10-bit H265/H264 decoding
System Memory – 1, 2 or 4GB LPDDR4 @ 3200 Mbps
Storage – eMMC module socket, micro SD card slot up to 128GB, M.2 NVME SSD socket
Video Output / Display Interface
HDMI 2.0a up to 4K @ 60 Hz
2-lane MIPI DSI via FPC connector
Dual independent display support
Audio – Via HDMI and 3.5mm audio jack; HD codec supporting up to 24-bit/96Khz audio
Camera – MIPI-CSI2 connector for camera up to 8MP
Connectivity
Rock Pi 4A – Gigabit Ethernet
Rock Pi 4B – Gigabit Ethernet with PoE support (additional HAT required), 802.11ac WiFi 5, Bluetooth 5.0 with on-board antenna
USB – 1x USB 3.0 host port, 1x USB 3.0 OTG port, 2x USB 2.0 host ports
Expansion – 40-pin expansion header with 1x UART, 2x SPI bus, 2x I2C bus,  1x PCM/I2S, 1x SPDIF, 1x PWM, 1x ADC, 6x GPIO, and power signals (5V, 3.3V and GND)
Misc – RTC
Power Supply – Via USB-C port supporting USB PD 2.0 (9V/2A, 12V/2A, 15V/2A, or 20V/2A) and Qualcomm Quick Charge 3.0/.0 (9V/2A, 12V/1.5A). It’s also possible to power the power via a 5V/3.4A power adapter, but it is not recommended
Dimensions – 85 x 54 mm
So the only real difference between model A and model B is the latter includes a wireless module, and optional support for PoE.



vraiment pas mal pour le prix (à partir de 39$)