I searched a little bit on the subject, but I couldn't find any clear answers, so I'm asking this question: Will the performance of a USB hub connected directly to the motherboard be shared between the devices plugged into the hub? How is the power AND data speed distributed in such a hub?
Here is the USB hub I am talking about.
Will the performance of a USB hub connected directly to the motherboard be shared between the devices plugged into the hub?
The hub is basically invisible. The hub's uplink ports still only have however much bandwidth they have, and that bandwidth can be used by the host to access any of the downlink ports.
How is the power AND data speed distributed in such a hub?
That's completely up to the host. The total power to all the downlink ports can't exceed the power available from the uplink port, since this hub has no separate power source. And the total speed of all downlink ports can't exceed the speed of the uplink ports. But how that's divided is completely up to the software on the host, the hub has no say.
It seems to me that an internal hub would still outperform an external hub, though, because the internal hub is tied into a faster access point (in my case, a PCI-E) than when an external hub is hooked in through a USB port, and sharing the bandwidth of that one access point across multiple USB ports. PCI-E = 16 gigatransfers per second (1000 times less latency and faster transfer speed than USB, which means it won't be the chokepoint, the USB 3.0 ports will). If I have 7 USB 3.0 ports sharing that PCI-E, which is usually broken into a number of lanes, it still won't make a dent, and all 7 will theoretically be moving at maximum speed for USB, even if in use simultaneously. If I put them through an external bus, however, 10 devices will be sharing the speed of one USB port chokepoint, where it's plugged into the PC, and I will be getting fractions of speed of the single USB port they all share. If two are running at the same time, 1/2 speed, 4 running at the same time, 1/4 speed, etc., down to 1/10 speed (50 MBps). Or am I missing something?
The hub you're looking at is actually two 4-port USB hubs in one unit. The two 4-port hubs connect to two USB ports on the motherboard via the single connector.
In a nutshell, each 4-port hub shares the bandwidth and power provided by the one USB port.
You're challenge is going to be in figuring out which of the 8 sockets belong to Hub1 and which belong to Hub2. I imagine it comes with a bit of documentation that tells you.
