The common unpowered hub (a misnomer?) does use the 500 mA given to it on it's host connection. If the devices that you plug into the hub (4 or 7 ports will not matter) exceed this supply then you need a powered hub.
Since powered hubs are cheep on newegg.com or geeks.com if I was getting a 7 port hub I'd get the powered one.
I NEED to upgrade my little laptop USB 4-port hub to a 7-port hub. I've noticed there are hubs that are "powered". What are the advantages to getting a powered hub vs. a non-powered hub?
The ports on my laptop are all USB 2.0, but unfortunately, there are only 3 ports. If it makes any difference, I'm on a PC with Windows XP Home SP2 with an AMD Mobile Sempron 2800 processor.
The peripherals to be connected include: printer, flatbed scanner, ipod, PDA, card reader, laptop cooler, and a mouse.
Any advice would be very much appreciated!