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: [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

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

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.

smarteyeball said:

The external drive will work at full USB 2.0 speeds regardless of laptop hub output.

As for external hubs, both are mains powered so if you want more gadgets - go for the 10 port. You are only limited by the number of ports on the hub.

Of course you are aware that you will still be limited to USB 2.0 speeds regardless of hub though?

As if you understood me totally. Am I right? indeed I have gotten the acquaintance that my Toshiba 2.0 interfaces will influence the behavior of 3.0 hub largely. It seems to urge me to replace my laptop with a high-end one. Anyway, I am considering...