What is the highest (theoretical) bandwidth you would get per port on a USB 3.0 hub?

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Insane NiTEmare

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While I understand there are many different sizes of USB hubs (as in amount of ports), I don't have any USB .0 devices; only USB 2.0 ones and one device I use my motherboard's USB 3.0 high-speed-charging support on.
1. If I was to buy a USB 3.0 hub, how many ports could I have on the hub to get at least USB 2.0 speeds (assuming USB 2.0 won't reach over 280MBit/s)?
2. Will my motherboard (ASUS M5A97 R2.0) support charging through the hub or will I need to use my other USB 3.0 port for that?
 
Solution
manofchalk
So...
You are asking us how many times 280Mb/s (your self imposed limit on USB2, its really 480Mb/s) divides 5Gb/s?
Roughly 18 times, but if you use the full bandwidth of USB2, roughly 10.

Charging through the hub is probably possible, but only a few low power devices would work. A USB port only puts out 5v, it cant run that much. Keyboards with USB hubs often cant support anything over .2mA, which excludes a lot of flash drives even.
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I'm looking the maximum bandwidth per port when splitting (compare to how in a parallel circuit you split with [Total Amps]/[Number of Routes]). My motherboard is only 3.0 so the ports base maximum is 5Gps not 10Gps (USB 3.1)
 
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manofchalk

manofchalk

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So...
You are asking us how many times 280Mb/s (your self imposed limit on USB2, its really 480Mb/s) divides 5Gb/s?
Roughly 18 times, but if you use the full bandwidth of USB2, roughly 10.

Charging through the hub is probably possible, but only a few low power devices would work. A USB port only puts out 5v, it cant run that much. Keyboards with USB hubs often cant support anything over .2mA, which excludes a lot of flash drives even.
 
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Insane NiTEmare

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The highest mean data rate USB 2.0 was recorded at was 280MBs, that's why I said 280mbs not 480mbs (I'm not using anything demanding through this, just a keyboard+mouse wireless combo, 2 game pads and an intuos4)

(edit) I questioned charging because USB 3.0 can output either more amps or more volts (but not both) to it's outlet. This should mean that each USB 2.0 device would receive sufficient power when connected to a supported USB 3.0 hub that's receiving all the extra amps to distribute.

(edit again) and as far as I can remember USB 3.0 wasn't clocked much higher than 1gbs on a single device anyway, and I'm not necessarily in the market for a useless external HDD when I could save and buy another internal 2TB HDD and swap out an old one (they need replacing anyway).
 
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manofchalk

manofchalk

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(assuming USB 2.0 won't reach over 280MBit/s)?
Click to expand...
The highest mean data rate USB 2.0 was recorded at was 280MBs, that's why I said 280mbs not 480mbs
Click to expand...
USB 3.0 wasn't clocked much higher than 1gbs
Click to expand...

You know there is a difference between Gb/Mb and GB/MB right? Getting that right might clear up a lot of the confusion you have.
Also to say "MBits" is confusing as hell. b is for bits, B is for bytes. There is a difference by a factor of 8 between them.



No it cant, USB standard dictate that a USB3 outputs a flat 5V, with an allowable .55V variance.

Max. voltage
5.00±0.25 V (pre-3.0);
5.00+0.25-0.55 V (USB 3.0)
http://en.wikipedia.org/wiki/USB

The Amperage can change, but your standard computer USB port is somewhere between .5A and 1A. Only charging devices output more than that (theirs a reason some cases and mobo's come with dedicated charging ports on them).
 
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Insane NiTEmare

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I'm solely talking Mbits, why would I talk about MB in linked data transfer? When talking about transfers and TRANSFERS ALONE mbs or mb/s would assume Megabits not MegaBytes or Mibibytes. As for Voltage variance I've gotten much higher than 6V out of my USB 3.0 ports so no; it can output more, and USB 3.0 was build to power with <2A at 5.5V, and I've seen a low-power <2A 3.3V option.

(edit) I'd rather not get into an internet fight. I just want to know if anyone's tried this and if you can truly split USB 3.0's speed over a selection of ports (thus getting a larger selection of USB 2.0 equivalent ports from a single USB 3.0 port)
'
(another edit) should it be noted JEDEC doesn't give a shit about names; I've heard Mega/Giga for binary and metric, and Mibi/Gibi for much of the same. On the other hand I've only heard Bit as an eighth of a Binary Byte (which only in a perfect world would be 1/8192 of a Binary Megabyte, because I don't remember the imperialistic like measurement bases off the top of my head)
 
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manofchalk

manofchalk

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I'm solely talking Mbits, why would I talk about MB in linked data transfer?
Click to expand...
Why would you write MB then?

In terms of pure bandwidth, you can fit 10 USB2 ports into USB3 without bottlenecking. I already answered that. Whether it actually breaks down like that, I have no idea, but something like this is so variable to the hub being used, the chipset and its drivers, what files its transferring and whatever is plugged into it that you will never get a proper answer.

Your asking how much can a USB hub power. I looked it up, and it says that a standard USB port on a computer outputs 5V and somewhere between .5A to 1A. In my experience, a two USB hub on a keyboard is pretty weak, only offering 100mA on each port (I was wrong with my initial statement of .2mA).
Everything I know and can find leads me to believe it wont be able to power much. If you say you can pull 6V at 2A out of a port, go do it, because I cant find anything that says you can (on a computer, USB3 sure as hell supports 2A, does your motherboard is the question).
 
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Insane NiTEmare

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I guess I'll look into a tested/reviewed super speed hub that supports an external power adapter
 
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