Rockchip RK3668: 44 TOPS NPU and PCIe 5.0 Above RK3588

Rockchip's RK3588 has powered a huge share of the high-end Arm single-board computers of the last few years. Its successor tier is now taking shape. The Rockchip RK3668, detailed in an application brief shared by Radxa and reported by LinuxGizmos on October 24, 2026, is a 6nm chip that lands above the RK3588 on Rockchip's roadmap, with a far stronger AI accelerator and server-class I/O. Engineering samples are targeted for the first quarter of 2027.

• CPU: six Arm Cortex-A725 cores at up to 2.5GHz plus two Cortex-A520 cores at up to 2.2GHz, Armv9.2, 64-bit only
• AI: a Rockchip NPU rated at 44 TOPS (sparse INT8), supporting formats from INT2 to FP16 including FP4, FP6 and FP8
• Memory and I/O: LPDDR6-10667 up to 64GB, four PCIe Gen 5 controllers, four SATA 3.1 ports and two 10GbE interfaces
• Timing: engineering samples targeted for Q1 2027, according to Rockchip's October 9 brief as summarized by SBCwiki

What's Inside the Rockchip RK3668?

According to LinuxGizmos, the CPU cluster pairs its eight cores with 4MB of L3 cache, 4MB of shared system-level cache and 4MB of SRAM, and adds SVE2 vector instructions plus Arm security features such as Memory Tagging Extension and Pointer Authentication. Graphics come from an Arm Mali-G2 Pro MC4 GPU at a projected 1.1GHz, worth about 1.23 TFLOPS of FP32 compute, with hardware virtualization for up to 16 virtual machines.

Memory is a major upgrade. The RK3668 supports LPDDR5 and LPDDR5X-8533 over a 64-bit bus or LPDDR6-10667 over a 96-bit bus. With LPDDR6, peak theoretical bandwidth reaches 128GB/s, which Rockchip conservatively derates to about 90GB/s of effective bandwidth. That matters a great deal for running language models locally, where memory bandwidth often limits token speed more than raw compute.

How Fast Is the RK3668 NPU for Local AI?

The 44 TOPS figure is a sparse INT8 rating, and SBCwiki lists it as 8.8 TOPS per core. More interesting than the number is the format list: low-bit weights such as W4A8 and W4A16, INT2 through INT16, and FP4 through FP16. Rockchip also lists support for Transformer models, mixture-of-experts workloads and speculative sampling, all techniques common in modern LLM inference. Those claims come from Rockchip's own brief, so real-world performance will depend on the software toolchain when boards arrive.

Connectivity Built for Edge Servers

The I/O list reads more like a small server than a typical SBC chip:

• PCIe: PCIe 5.0 plus PCIe 3.0 lanes, with some high-speed functions sharing configurable PHYs
• Networking: two 10 Gigabit Ethernet interfaces and two RGMII Ethernet ports
• Storage: UFS 4.0, eMMC 5.1, NVMe, SD and four SATA 3.1 controllers
• Video: 8K at 120fps decoding across H.265, H.264, VP9, AV1 and AVS2, 8K60 encoding, and output to two 8K60 or six 4K60 displays
• Safety: a dual Cortex-M52 safety island for industrial designs

When Will RK3668 Boards Arrive?

Not right away. Engineering samples are targeted for Q1 2027, so finished boards will likely follow later in that year. Rockchip's roadmap still lists the RK3688 as the future flagship above it. Until then, RK3588 platforms such as the Jetway SMC-ARK1 SMARC module remain the practical choice, but the RK3668 shows where Arm SBCs and compact NAS boxes are heading next: more AI, more bandwidth and much faster storage. Keep an eye on our mini computer coverage for the first boards.

Sources: LinuxGizmos — October 24, 2026; SBCwiki: Rockchip RK3668 — accessed October 27, 2026.