[QUOTE=Dee;2573510]900ma is the minimum requirement,[/quote]And unless stated otherwise (i.e. The documentation of your motherboard or computer states something like “USB port up to xx mA”), you can’t expect more than the minimum defined by the specs.
but I haven’t seen a motherboard with USB3 that can’t supply 1.8A, some as much as 3A.
If this is stated in the product documentation, then this is okay IMO.
Spec or no spec, the real world is often different to the spec.
If no component manufacturer would design their stuff spec compliant, you wouldn’t have a new, shiny Sandy Bridge system that works, but a collection of single parts that won’t fit together.
[QUOTE=SeÃ¡n;2573515]Generally the power rating is peak, which is when the disk spins up. I highly doubt it draws 1A continuously.[/quote]Accepted as true.
This Samsung also draws less power than my other USB portable HDDs. For example, I have a Western Digital Passport 250GB, which will not power up on my PC’s front ports and certain media player USB ports,
Such a piece of junk has to be returned to vendor.
Usually if the port does not provide enough power, one of the following things will happen:
The drive does not spin up. E.g. the WD passport’s LED will flash dark/bright blue continuously to indicate that it’s not receiving enough power.
Or intermittent spin-up retries until you pull the plug. HDDs love that.
The USB’s protection kicks in and disables the port, then Windows displays “Power surge on hub port - A USB Device has exceeded the power limits of its hub port”.
This is solely based on software and needs proper power demand signalling by the device.
A USB device has [B]requested [/B]more power than the hub can provide.(…)
Most external drives are cheating here and do not properly request its power demand.
I never seen this error with any hard disk, so this webcam must have drawn a serious amount of current.
Bus powered HDDs are cheating.
Finally, I have never seen or even heard of a USB host or PSU being damaged by a USB device drawing too much power.
Want the fried USB hub that’s lying in my drawer? Yes, it had its own power supply.