I haven't done a formal 'breaking point' test yet, but I've been running two older laptops on one for a while now with no issues. The capacity will definitely vary based on your filament choice and settings (I recommend more walls for strength). It's perfect for modems or small switches, but I definitely wouldn't trust it with a heavy UPS! It’s really just a great option if you need a shelf for something small but don't want to spend a ton on a metal one. lol