Gaming Handhelds Compared: Steam Deck, ROG Ally and Legion Go on Published Specs

Three philosophies of handheld gaming

The modern handheld PC market settled into three distinct design philosophies, each visible directly in the vendors' published materials. Valve's Steam Deck runs SteamOS on a custom AMD APU: a single integrated platform where hardware, operating system and storefront are all controlled by one company. ASUS's ROG Ally X runs Windows 11 on AMD's Ryzen Z1 Extreme, positioned as a portable gaming PC first and a console-like device second. Lenovo's Legion Go takes the same Windows-plus-Z1-Extreme approach but adds a hardware twist: detachable controllers that turn the 8.8-inch tablet into something closer to a hybrid of Switch and gaming monitor.

None of these approaches is wrong on paper — but the published specs tell you more about who each device is for than any marketing copy does. Everything below is drawn from Valve's Steam Deck page, ASUS's ROG Ally X product page and Lenovo's Legion Go pages, all read on 19 October 2026.

Displays: what each vendor publishes

The display is where the three devices diverge most sharply. Valve publishes a 7.4-inch 1280×800 HDR OLED panel with up to 90Hz refresh on the Steam Deck OLED. ASUS publishes a 7-inch 1920×1080 touch panel at 120Hz with FreeSync Premium, 500 nits brightness, 100% sRGB and a 7ms response time, protected by Gorilla Glass (ASUS lists both Victus and DXC coating treatments on the page). Lenovo publishes the largest panel of the three: an 8.8-inch 2560×1600 (QHD+) IPS touchscreen, 16:10, 144Hz, 500 nits, 97% DCI-P3, with resolution scaling down to 800p and refresh down to 60Hz supported for performance and battery saving.

The trade-off is physics: the Legion Go's QHD+ panel has roughly 2.7× the pixels of the Steam Deck's display, which costs GPU throughput and battery unless you use Lenovo's documented downscaling to 800p. The ROG Ally X's 1080p panel sits in the middle — higher refresh than Steam Deck, lower resolution than Legion Go.

Silicon: custom APU versus Ryzen Z1 Extreme

Valve's page describes the Steam Deck's chip as a custom AMD APU "optimized for handheld gaming… a Zen 2 + RDNA 2 powerhouse," and its spec block lists 8 RDNA 2 compute units at 1.6 GHz, up to 1.6 TFLOPS FP32, with an APU power envelope of 4–15 W. Both the ROG Ally X and Legion Go use AMD's Ryzen Z1 Extreme, which ASUS documents as Zen 4 architecture with RDNA 3 graphics, 8 cores / 16 threads, a 4nm process and 8.6 teraflops; Lenovo's page repeats the same Zen 4 / RDNA 3 / 8-core / 8.6 TFLOPS figures for the Z1 Extreme configuration it sells.

On published numbers the Z1 Extreme's 8.6 TFLOPS figure dwarfs the Steam Deck's 1.6 TFLOPS — but the comparison has caveats the spec sheets never spell out. Different architectures, different power envelopes and different thermal designs mean teraflops do not translate one-to-one into playable frame rates. ASUS publishes an in-game average FPS chart for the Ally X (Cyberpunk 2077, Forza Horizon 5, Diablo IV, Call of Duty: Modern Warfare II, Elden Ring) measured in Turbo mode plugged in at 30W — with the test system configuration listed — which is the kind of disclosure Valve and Lenovo do not publish on their product pages. Real-world sustained performance on any of the three depends on the power limit you choose and the game you play.

Memory and storage expansion

The Steam Deck ships with 16 GB of LPDDR5 RAM on board, per Valve's spec block. ASUS lists "up to 24GB of LPDDR5X RAM" for the ROG Ally X (the review-unit configuration quoted in its FPS chart lists 24GB), and up to 1TB on an upgradeable M.2 2280 PCIe Gen 4 SSD. Lenovo publishes 16GB of 7500MHz LPDDR5X on board for the Legion Go, with 256GB, 512GB or 1TB PCIe 4.0 NVMe storage on an M.2 2242 module — note the shorter 2242 form factor, which narrows the replacement-SSD market compared with the Ally X's standard 2280 slot.

All three support microSD expansion, but not equally: Valve documents a high-speed UHS-I slot (SD/SDXC/SDHC), ASUS documents UHS-II on the Ally X, and Lenovo says the Legion Go's slot takes cards up to 2TB. For SSD upgrades, the Ally X is the friendliest platform on published specs: a standard-length M.2 2280 slot, versus the Legion Go's 2242 and the Steam Deck's single non-user-replaceable-by-design storage configuration on current models Not verified — Valve's spec block lists SSD options without documenting a user-replacement procedure.

Battery capacity and charging

Battery is where the published numbers are most revealing. Valve lists a 50Whr battery on the Steam Deck OLED with a candid "3–12 hours of gameplay (content-dependent)" range and a 45W power supply. ASUS lists an 80Wh battery on the ROG Ally X — the largest of the three — with "redesigned ergonomics for long gaming sessions" and dual USB-C ports. Lenovo lists a 49.2Whr two-cell battery with Super Rapid Charge support and a Power Bypass Mode that lets the device run from the adapter without cycling the battery, plus a 65W adapter in the box and a documented 900mAh cell inside each controller.

Controls, modes and software

The operating systems differ as much as the hardware. The Steam Deck runs SteamOS (Valve's page references it in the device's software context); ASUS documents Windows 11 on the ROG Ally X, with Armoury Crate SE as its control software (the FPS-chart test configuration lists Armoury Crate SE v1.5.5); Lenovo documents Windows 11 Home on the Legion Go with its Legion Space hub software and detachable Legion TrueStrike controllers, including an FPS Mode that repurposes the right controller as a vertical mouse for shooters.

The detachable-controller design is unique to the Legion Go among these three on published materials: Lenovo lists separate dimensions and weights for the base module (210 × 131 × 20 mm, 640g) and the unit with controllers attached (299 × 131 × 41 mm, 854g), plus a touchpad and a controller base accessory. ASUS adds a fingerprint sensor to the Ally X's documented hardware list. Valve documents its control layout as part of the deck's integrated design with trackpads Not verified on this fetched page — the spec block we read covers display, compute, storage and battery, while trackpad details live in Valve's broader product materials we did not fetch for this article.

What the spec sheets do not tell you

Published specs have consistent blind spots across all three vendors. None of the product pages we fetched publishes sustained frame rates across a common set of games (ASUS publishes its own chart for five titles under a fixed 30W Turbo configuration; Valve and Lenovo publish none on these pages). None publishes screen-on battery life for identical workloads. And pricing is regional, promotional and volatile: Valve's fetched page carried a limited-edition White OLED model at $679 USD announced for November 2024, and current street prices for all three devices change with sales and refreshes — treat any price you see as a snapshot, not a spec.

Weight is another gap: Lenovo documents its two weights explicitly; the ASUS and Valve pages we fetched do not state device weight in the spec sections we captured Not verified. If handheld weight matters to you, confirm it on the vendor's full datasheet before buying.

Decision table: which handheld fits whom

All three are legitimate entries with real engineering trade-offs. The honest summary from published specs: the Steam Deck trades raw silicon for a tuned, low-power integrated experience; the Ally X trades screen real estate for battery capacity and upgradeability; the Legion Go trades weight and battery headroom for the largest, highest-refresh display and its detachable form factor. Decide which trade you'd actually make before comparing prices — that order is what the spec sheets reward.