SoC – Rockchip RK3328 quad core Cortex A53 processor with ARM Mali-450MP2 GPU
System Memory – 1, 2, or 4 GB LPDDR3 @ 1866 MHz
Storage – eMMC flash module socket + micro SD card slot + 128 Mbit SPI flash
Video & Audio Output – HDMI 2.0a up to 4K @ 60 Hz with HDR10 and HLG support, 3.5mm AV port (composite video + stereo audio)
Video Codec – 4K VP9, H.265 and H.264, 1080p VC-1, MPEG-1/2/4, VP6/8
Connectivity – Gigabit Ethernet
USB – 2x USB 2.0 ports, 1x USB 3.0 port
Expansion Headers
40-pin Pi-2 Bus with GPIOs, 2x I2C, Analog inputs, UART, SPI, and power signals (5V, 3.3V, and GND)
22-pin Pi-P5+ Bus with GPIOs, I2S, S/PDIF, Ethernet, and power signals (5V, 3.3V, and GND)
Misc – IR receiver; power, recovery  & reset buttons; eMMC jumper
Power Supply – 5V/3A via 3.5mm/1.35mm power barrel
Dimensions –  85 x 56 mm

ROCK64 board may be sold for around $25 (1GB RAM), $35 (2GB RAM) and $45 to 50 (4GB RAM) excluding shipping