Macbooks' bus power?

Do any of you know anything about the usb bus power a macbook can put out?

Here's all my computer will tell me:

USB Bus:

Host Controller Location: Built In USB
Host Controller Driver: AppleUSBUHCI
PCI Device ID: 0x27c9
PCI Revision ID: 0x0002
PCI Vendor ID: 0x8086
Bus Number: 0x3d



Is the bus power in my macbook limited?? I think the WD passport I might be getting requires between 500 and 650 mA, or something like that.

I'll probably end up getting a MyBook Essentials if I need the extra usb power hub thing because I don't want to have to order an extra cable, cuz they're out of stock right now on the WD site, and that's $10 extra I don't really want to spend.

All I can tell you is I have no issues at all with a WD Passport Bus Powered HDD on my iBook G4 1.33Ghz. Works every time.

OK. I shouldn't have any problems then.
Thanks.