![]() |
![]() |
#1 (permalink) |
Full Member
Join Date: Mar 2012
Posts: 45
|
![]()
Possibly the wrong terminology in the title
![]() If I have a 4 port USB 3 hub plugged into a USB 3 port on a desktop computer - - - Can I plug 2 or more USB 3 drives into the hub and get USB 3 speeds on all devices? Lets assume all the devices are externally powered via a wall socket. Depending on the response to this question, I might ask another later :-) I'm guessing that the speed will be decreased the more drives are connected and transferring files at the same time. But this is just for interests sake. I'm not having any issues at all. Any hardware experts out there? Cheers, Paul Last edited by West Swan; 13. Sep 2013 at 11:39 AM. |
![]() |
![]() |
![]() |
#2 (permalink) |
Senior Member
Join Date: Jul 2010
Location: New Zealand
Posts: 1,741
|
![]()
If you have multiple USB 3 drives attached to one USB 3 controller on a USB network where all controllers and devices are USB 3 then overall bandwidth is limited and the throughput of individual drives would be constrained.
There are several factors that would also need to be considered in most real world scenarios including:
USB 3 is full-duplex, transfers both ways at the same time, rather than half-duplex, transfers one direction at a time, as used by USB 1/2. That is why USB 3 devices can initiate communication with the USB host, ie can speak up, whereas USB 1 & 2 controllers poll the devices which cannot initiate anything, ie only speak when they are spoken to (polled). USB 3 hubs have separate controllers for USB 3 and USB 1/2 devices so there is little impact on USB 3 throughput from legacy devices. A USB device has a limit of 32 endpoints so it is unlikely but theoretically possible that throughput would be constrained by trying to communicate with too many devices at the same time. For others who are reading here, note that newer USB specifications introduce new functions and features and not just improvements in raw bandwidth. USB 1 provided two speeds Low-Speed for devices like mice and Full-Speedfor devices like memory and disk. USB 2 has two types of controller: you need the Hi-Speed one to get the higher raw bandwidth but I've seen very few without USB 2 ports that aren't Hi-Speed. All USB 2 devices have other features like the ability to communicate with one another without a separate host. Here's the maximum raw speeds anyway: USB 1 1.5Mbps Low USB 1 12Mbps Full USB 2 12Mbps Full USB 2 480Mbps Hi USB 3 5Gbps Super
__________________
Better to light a candle ... than to curse the darkness. |
![]() |
![]() |
![]() |
Thread Tools | |
Display Modes | |
|
|