BGA ST1 socket: CPUs, chipsets and cooler fit

A soldered handheld package

ST1 follows the same rule as every BGA package on this site: the processor is soldered once at the factory and stays with the board for life. There are no pins to bend and no lever to lift, but there is also no upgrade path. A handheld buyer lives with the chosen APU, and the 16 GB memory pool is permanent. AMD lists Ryzen Z2 A with 4 cores and 8 threads at 2.8 GHz base and up to 3.8 GHz boost, which matches the Van Gogh envelope from Steam Deck.

The package choice shapes the handheld. ST1 needs quad channel LPDDR5 layout with short traces for power, and 6400 MT per s is already enough to ask for careful routing. The 4 to 15 W APU power band suits small bodies with a single fan and heat pipe. Compatibility across Van Gogh generations still depends on firmware, so a newer Z2 A board needs system software that knows the SKU.

Memory, expansion and cooling

Memory on ST1 is a fixed answer. Soldered LPDDR5-6400 in quad 32-bit channels with 16 GB is the Deck class configuration, and capacity joins the APU as a permanent choice. Buyers who load large game textures should take 512 GB or 1 TB of NVMe storage at order time, since the APU and RAM cannot be changed later. Display output runs through USB-C alternate mode to docks, with 1280 by 800 panels in handheld mode.

Expansion comes from PCIe Gen3 lanes, plus USB-C, microSD and wireless. The lanes usually serve one NVMe drive and the wireless card, with the exact split fixed per handheld. Boards that need more than Van Gogh offers cannot add a desktop chipset, so I/O stays at the handheld baseline.

Cooling has no retail answer on ST1. The same package spans 6 W efficient modes to 20 W configured peaks, and the fan, heat pipe and chassis vents are drawn for that product. Sustained play settles at the power the body rejects, so reviews of the exact handheld predict real behavior better than the TDP number alone.

Where ST1 designs are used

ST1 covers handheld PC gaming: Steam Deck from 2022 and Ryzen Z2 A handhelds such as the ROG Xbox Ally from June 2025. The single Van Gogh die scales across LCD and OLED Deck revisions with 6 nm Sephiroth refresh silicon, plus the Z2 A entry tier with the same 4-core and 8-CU layout. All share the 15 W TDP with 6 to 20 W configurability for battery versus performance modes.

Desktop builders never meet ST1 silicon on a socketed board. The same Zen 2 cores appear on AM4 in desktop packages with DDR4, while ST1 stays the handheld home of Van Gogh. Designs that outgrow 4 cores or 8 graphics compute units move to FP8, which carries Phoenix and Hawk Point silicon with wider memory and more lanes. The LGA, PGA and BGA: CPU package types explained guide covers the soldered tradeoff behind handheld designs.