Yeah, I figured something like that. I think indeed the problem with the other "powered" hubs is that they do not have a beefy enough power supply. They'll have like 7 ports but only come with a 600ma power supply, so as soon as you plug in more than 1 device that draws power from the hub, it falls flat on its face, because the powersupply can't deliver enough to power more than a single device at a time. which of course kinda defeats the whole purpose of having a hub!
