RK3399 based Raspberry Pi clone starts at $75 LinuxGizmos.com In May, FriendlyElec launched a $129, 4GB RAM NanoPC-T4 SBC that more or less tied with Shenzhen Xunlong's 2GB Orange Pi RK3399 as the most affordable SBC based on Rockchip's hexa-core RK3399 SoC. At 100 x 64mm, it was also the smallest.