Only two USB 3 busses

[woodbine]

I had a look at system report for my new MacMini 2012 and it says only two USB 3 ports and two USB 2 ports.
Is this correct?

[flopticalcube]

That is correct. Ivy Bridge CPUs have two USB 3 bus controllers built in and there is no other onboard bus controller on the logic board.

[dmk1974]

So 2 ports per bus then? You make it sound like only 2 of the 4 ports are at USB3 speed. Per Apple's site, all 4 ports are USB3.

[WLS]

Is one bus controller for internal devices and the other for external? E.G are all 4 of the USB rear ports on the same bus?

[paulrbeers]

Originally Posted by dmk1974

So 2 ports per bus then? You make it sound like only 2 of the 4 ports are at USB3 speed. Per Apple's site, all 4 ports are USB3.

This is the standard setup for almost all computers. Any computer you buy, generally does not have a 1:1 BUS to port ratio, usually it is 1:2 bus to port (sometimes the ratio is even worse). Some laptops that have very few USB ports will have a 1:1 (if the only have 2), but even a friend's Fujitsu 12" laptop I used the other day had 3 USB ports and it was split with 1:1 on one USB port and 1:2 with the other two.

[madrag]

Originally Posted by paulrbeers

This is the standard setup for almost all computers. Any computer you buy, generally does not have a 1:1 BUS to port ratio, usually it is 1:2 bus to port (sometimes the ratio is even worse). Some laptops that have very few USB ports will have a 1:1 (if the only have 2), but even a friend's Fujitsu 12" laptop I used the other day had 3 USB ports and it was split with 1:1 on one USB port and 1:2 with the other two.

So is there a way to know which ports are USB3? (via the system profiler porbably, correct?)

This is sad, I thought it had four USB3 ports

[paulrbeers]

Originally Posted by madrag

So is there a way to know which ports are USB3? (via the system profiler porbably, correct?)

This is sad, I thought it had four USB3 ports

You misunderstand, they are ALL USB3, just that two will share USB3 bandwidth so if you plugged two high bandwidth items into two USB3 ports that share the same BUS, they might experience a slow down. Granted USB3 is faster than any mechanical hard drive can output (or two for that matter), so it would have to be something like hooking SSD's via a USB3 port that you might see this issue.

EDIT: Think of it like 2 port USB hubs.

[fa8362]

Originally Posted by madrag

So is there a way to know which ports are USB3? (via the system profiler porbably, correct?)

This is sad, I thought it had four USB3 ports

It does. All the USB ports on the rear are 3.0.

[philipma1957]

the mini is auto detect. plug in 4 usb3 devices restart the machine and all 4 ports will show usb3. plug in all 4 usb2 devices the mini will show 4 usb2. any combo it will show.

Now as to the ability to run 4 usb3 devices at full speed at the same time most likely it can't do it. you could try to test it but not sure if it can be done that easy.

[rkahl]

What's the difference between USB 3 Hi-Speed and USB 3 SuperSpeed?

[fa8362]

Originally Posted by rkahl

What's the difference between USB 3 Hi-speed and USB 3 Super-speed?

There is no USB 3 hi-speed. Any reference to hi-speed is USB 2.

[rkahl]

Originally Posted by fa8362

There is no USB 3 hi-speed. Any reference to hi-speed is USB 2.

My 2012 Mac Mini system report says that I have a USB 3.0 Hi-Speed Bus and a USB 3.0 SuperSpeed Bus. What's the difference?

[fa8362]

Originally Posted by rkahl

My 2012 Mac Mini system report says that I have a USB 3.0 Hi-Speed Bus and a USB 3.0 SuperSpeed Bus. What's the difference?

It's telling you that you have a USB 2 bus...I think.

[rkahl]

Originally Posted by fa8362

It's telling you that you have a USB 2 bus.

Sorry to sound dumb, but how do you know if you are plugging your external hard drive into a USB 2 or a USB 3 port?

[fa8362]

Originally Posted by rkahl

Sorry to sound dumb, but how do you know if you are plugging your external hard drive into a USB 2 or a USB 3 port?

As far as I know, all the rear ports are USB 3. If you have a USB 2 device hooked up though, it might read as something lower than USB 3 super speed.

[madrag]

Originally Posted by paulrbeers

You misunderstand, they are ALL USB3, just that two will share USB3 bandwidth so if you plugged two high bandwidth items into two USB3 ports that share the same BUS, they might experience a slow down. Granted USB3 is faster than any mechanical hard drive can output (or two for that matter), so it would have to be something like hooking SSD's via a USB3 port that you might see this issue.

EDIT: Think of it like 2 port USB hubs.

Originally Posted by fa8362

It does. All the USB ports on the rear are 3.0.

Thanks for the explanation.