Physical Dimensions & Thickness: The Anbernic RG405M has a horizontal bar chassis measuring 162 × 73.6 × 15.8 mm, while the ASUS ROG Ally X uses a horizontal bar chassis measuring 280.2 × 114 × 36.9 mm. In width, the Anbernic RG405M is 118.2 mm (42.2%) narrower than the ASUS ROG Ally X. In height, the Anbernic RG405M is 40.4 mm (35.4%) shorter than the ASUS ROG Ally X. In chassis thickness (depth), the Anbernic RG405M is 21.1 mm (57.2%) slimmer than the ASUS ROG Ally X (15.8 mm vs 36.9 mm).
Footprint Area & Weight: Calculating surface footprint (width × height), the Anbernic RG405M occupies 11,923 mm² (119.2 cm²), compared to 31,943 mm² (319.4 cm²) for the ASUS ROG Ally X—a footprint difference of 20,020 mm² (62.7%). On the scale, the Anbernic RG405M weighs 265g versus 678g for the ASUS ROG Ally X, representing a 413g (60.9%) weight difference (Anbernic RG405M is lighter).
4:3 vs 16:9 Effective Viewable Screen Size: For classic 4:3 retro games (PS1, SNES, N64, Dreamcast), the Anbernic RG405M's 4" (4:3) panel yields a 4" 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 1.72" larger active 4:3 diagonal (104.5% more active display area). For 16:9 widescreen content (PSP, Switch, streaming), the Anbernic RG405M delivers a 3.67" effective diagonal (75% screen usage) versus 7" (100% screen usage) on the ASUS ROG Ally X, making the ASUS ROG Ally X larger by 3.33" (+263.5% active 16:9 area).
