Physical Dimensions & Thickness: The Anbernic RG28XX has a horizontal bar chassis measuring 125 × 56.5 × 16.5 mm, while the ASUS ROG Ally X uses a horizontal bar chassis measuring 280.2 × 114 × 36.9 mm. In width, the Anbernic RG28XX is 155.2 mm (55.4%) narrower than the ASUS ROG Ally X. In height, the Anbernic RG28XX is 57.5 mm (50.4%) shorter than the ASUS ROG Ally X. In chassis thickness (depth), the Anbernic RG28XX is 20.4 mm (55.3%) slimmer than the ASUS ROG Ally X (16.5 mm vs 36.9 mm).
Footprint Area & Weight: Calculating surface footprint (width × height), the Anbernic RG28XX occupies 7,063 mm² (70.6 cm²), compared to 31,943 mm² (319.4 cm²) for the ASUS ROG Ally X—a footprint difference of 24,880 mm² (77.9%). On the scale, the Anbernic RG28XX weighs 123g versus 678g for the ASUS ROG Ally X, representing a 555g (81.9%) weight difference (Anbernic RG28XX is lighter).
4:3 vs 16:9 Effective Viewable Screen Size: For classic 4:3 retro games (PS1, SNES, N64, Dreamcast), the Anbernic RG28XX's 2.83" (4:3) panel yields a 2.83" effective diagonal (100% full screen without black bars (native 4:3)), while the ASUS ROG Ally X's 7" (16:9) panel yields a 5.72" effective diagonal (75% active screen area with vertical pillarbox bars on the sides (native 16:9)). This gives the ASUS ROG Ally X a 2.89" larger active 4:3 diagonal (308.5% more active display area). For 16:9 widescreen content (PSP, Switch, streaming), the Anbernic RG28XX delivers a 2.6" effective diagonal (75% screen usage) versus 7" (100% screen usage) on the ASUS ROG Ally X, making the ASUS ROG Ally X larger by 4.4" (+626.2% active 16:9 area).