External USB 3.0 Hub ,can it behave normally or ideally?

I am currently using a Toshiba Satellite L535 laptop that comes with built in USB 2.0 ports. From my understanding, a USB 2.0 port can provide a maximum of 2.5W Power Output (5V x 500mA) and a USB 3.0 port can provide a maximum of 4.5W Power Output (5V x 900mA). Please tell me if I have a wrong cognition.

I am thinking of purchasing an external USB 3.0 hub and connect to my existing USB 2.0 port on my laptop. But after connecting the hub to my current USB 2.0 port, I wonder if the ports on the hub perform ideally as an USB 3.0 port by providing a maximum of 4.5W Power Output. I chose a used brand as a keyword to search online. I conclude two choice as the followings:

Amazon.com: UNITEK USB 3.0 Hub 4 Ports with 5V 4A Power Adapter Power Switch USB 3.0 cable, Support Windows XP / Vista / 7 / 8 / Mac OS X 10.8.4 / Linux, Black [VIA VL812 Chipset]: Computers & Accessories

Amazon.com: [10 Port usb3.0 Hub] Unitek USB 3.0 Hub 10 Port with 12v 4a Power Adapter a to B Cable Compatible with Windows Vista / Win7 (32/64-bit) and Mac Os 9.x or Latest Version: Computers & Accessories

If I prefer the gadget with more ports, is there any limit for the number? Or the less the better?

Please advise as you wish.

 

It wont. Your hub will be limited to the amount of power supplied via the one usb port that you plug in into. Anything not powerhungry shud be ok but perhaps not a mechanical keyboard lit like a christmas tree and other peripherals like external hdd.

 

Powered hubs get powered from the hubs ac adaptor. But some hubs, not all, need a proper signal from a computer before they supply power. This might be an issue if not plugged into a usb 3.0 port.

I think Toshibas have a special powered usb mode, mostly for powering the usb when the computer is off. Check in bios for it. Not sure if it increases amps though, but it might.

 

I thought the same as you said originally. But I suppose it will work normally as I saw there is a power adapter attached. I believe it will load as much as it stated and avoid the problem of power supply shortage. Am I right?

 

eh..I did not understand much. Did you also mean that there might be some power supply issue when I use this usb 3.0 gadget with my Toshiba ?

 

Yes, I think the above posters overcomplicated things. Both of the hubs you linked to ship with AC adapters. And putting a USB3.0 device into a USB2.0 port will drop everything down to USB2.0 specs - and since the hubs are AC powered, they won't draw anywhere near the limit current for USB2.0 or 3.0.

As long as this is plugged in and the hub is plugged into the computer it will work. Unless the hub sucks.

 

As long as the AC adapter for the hub is plugged in, powering devices will not be an issue. The hubs you posted are rated for 5v x 4A (4000mA) meaning it can power or charge multiple devices no problems.

Speed wise you will be limited to your laptops USB2.0 port.

 

Yes, the speed will be limited to your laptop's USB 2.0 port.
There are few reviews of those hubs you posted. Don't know how it works and I always suggest people read more reviews before ordering. If you need more options, I would recommend the HooToo. I have one of their bus-powered 7-port USB 3.0 Hub. It got decent reviews on Amazon. Amazon.com: HooToo® HT-UH006 USB 3.0 Hub 7-Port Bus-Powered (5V/3A Power Adapter, Latest VIA VL812 Chipset, 3.3 feet USB 3.0 Cable), Backward Compatible with USB 2.0 and Supporting Windows / Mac / Linux OS: Computers & Accessories

 

There are some powered hubs that will supply power with out a computer, those are optimal. There are others that that need to be plugged into a valid port to supply power. I hope that makes more sense. Next, if the power adaptor supplied with hub is outputting 5 volts at 4 amps, that is 20 watts total. 20 divided by four ports is five watts a port. If the other is 12 volts at 4 amps, that is 48 watts, or 4.8 per port. That is if the numbers listed in the titles above are right, and if all ports are used. If less ports are used it may allow for more power per port.