Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Can I connect 7 USB Portable Hard Disks using this hub? Does it work?
Document: I purchased the USpeed 7-port hub shortly after purchasing my Macbook Pro with Retina Display. I am presently using it with a mixture of both USB 2 and USB 3 devices including two USB 3 external hard disks. As soon as I received the hub, I unpackaged, connected it up and plugged it into a USB 3 port on my MBPR. The two USB 3 HD's plugged into the hub were not mounted, so I rebooted the MBPR.
I bought this for my wife's computer, but I really like it. Having 36W feeding the USB 3.0 ports really make this a great USB hub.I would recommend this for those who have limited USB 3.0 ports, and need to connect additional USB 3.0 devices. It works good for expansion hard disks.
Been using it about a week and so far so good. I am using it with several devices connected, including a USB 3.0 powered portable hard drive. In addition, I am using it on my new iMac with USB 3.0 connections without any issues. On this version all 7 inputs are USB 3.0.
This is a nice hub for those who travel or who need to connect a few simple devices to your system. USB mice, keyboards, USB flash drives and most external hard drives will work on this hub. However, be careful using the more power-hungry devices like large external hard drives which will not work.
After talking w/Apple, this seems to be their problem, not the hub's, and everything else I've got on the hub: external hard disks, keyboard, printer, etc... runs just fine. So, don't buy this - or ANY other USB hub, I tried another and it also didn't work with the cd/dvd reader - if you primarily want to run the external cd/dvd reader through it. Apple said they'd probably have to release an update for the PROM to fix it.
With 2012 MacBookPro I wanted 3.0 USB hub to support external 3.0 usb hard disks for storage. I got this brand because I found it at amazon.com with many very good reviews and price.However, now find that the hubs are not reliable, unpredictable:  the external disks are often not mounted and/or dropped periodically and/or not detected at all. At other times they work perfectly as desired.I missed the part about Logitech!
First Hub:  This hub did not work with a hard disk docking station.To backup my disks, I had put together a USB 3.0 subsystem . Putting together a Uspeed USB 3.0 PCI-e card w/4 ports + this Uspeed USB 3.0 hub + Cavalry EN-CAHDD2BUC3C-ZB USB 3.0 HDD dock + a hard disk, did not work. The Disk was not recognized by the system and was displayed as an Unspecified USB device.1.
I ordered two of these for a client with a new Apple MacBook Pro - one for each of his offices. He is a very demanding Graphic Designer and had many USB peripherals to connect from his previous install using USB 2.0 hubs. The primary issue was to add a USB 3.0 Hard Drive to each office and still have the older devices work properly but not spend a fortune or add an additional device to his desks. This product met every need and was very cost effective.
It works well at a reasonable price. Some people complain or comment about the fact that this unit has to be plugged in to the power adapter to work, but in my experience unpowered USB hubs, especially USB 3.0 hubs, are not very reliable. Just remember that ultimately this hub is using one USB 3.0 port on your system so you can't hang 7 USB 3.0 hard drives off of it and expect them to all transfer at full USB 3.0 speeds simultaneously.
I recently purchased an Acer Iconia w700 windows 8 tablet. I purchased the USB hub for the tablet when I am using it without the docking station but need more than the one USB 3.0 port. I thought this would be perfect. Problem is it doesn't work with my wireless mouse (USB 2.0) and sometimes - not always - it won't work with my new 500Gb WD Passport portable HD. It is intermittent so I'm not sure what the deal is there.
Answer: I am currently driving three WD My Book hard discs from the hub (2 Tb, 1Tb, 0.5 Tb), plus a printer and a scanner with no problems.