Mediatek’s flagship phone processor

Mediatek has adopted Arm’s top-end Cortex-X925 CPU in its second-generation ‘all big core’ phone processor – Dimensity 9400, made by TSMC on a 3nm process.

The X925 runs at up to 3.63GHz and has 2Mbyte of L2 cache, and shares the IC with three Cortex-X4 cores (1Mbyte L2 cache) and four Cortex-A720 cores (512kbyte L2 cache). These all share 12Mbyte of L3 cache.

The ‘all big’ branding comes from having no energy-saving processes from Arm’s big.Little concept – which would have meant replacing some of the A720s with A520 cores in this case.

“This design offers 35% faster single-core performance and 28% faster multi-core performance compared to MediaTek’s previous generation flagship, Dimensity 9300,” according to the Taiwanese company, which added: “Dimensity 9400 is up to 40% more power-efficient than its predecessor.”

A new generation of the company’s own neural processor is included, making it the “first mobile chipset to offer on-device LoRA [low-rank adaptation of large language models] training, on-device video generation, and developer support for agentic AI”.

An ‘agentic AI engine’ is included to turn traditional AI applications into agentic AI applications, and the company is working with developers to offer a unified interface between AI agents, third-party APKs and models that run both edge AI and cloud services – allowing models to work with many different third-party APKs – it said.

Gaming performance is seen to be a selling point – the IC has 12 cores of Arm latest Immortalis-G925 GPU, offering up to 40% faster ray-tracing performance compared to Mediatek’s previous flagship.

There is so much else going on inside this chip, so just picking a couple of aspects:

• The satellite navigation hardware covers GPS L1CA+L5+L1C, BeiDou B1I+ B1C + B2a +B2b, Glonass L1OF, Galileo E1 + E5a + E5b, QZSS L1CA + L5 and NavIC L5.
• Its Wi-Fi interface handles Wi-Fi 7 (a/b/g/n/ac/ax/be) with triple band triple concurrency and a 7.3Gbit/s peak data rate.