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woodbine

macrumors regular
Original poster
Aug 8, 2010
197
14
Bath, UK
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?
 

dmk1974

macrumors 68020
Sep 16, 2008
2,387
462
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

macrumors 65816
Jul 10, 2008
1,288
109
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

macrumors 68040
Dec 17, 2009
3,963
123
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

macrumors 6502
Nov 2, 2007
371
92
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

macrumors 68040
Dec 17, 2009
3,963
123
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.
 

philipma1957

macrumors 603
Apr 13, 2010
6,365
251
Howell, New Jersey
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

macrumors 65816
Jul 29, 2010
1,021
0
What's the difference between USB 3 Hi-Speed and USB 3 SuperSpeed?
 
Last edited:

fa8362

macrumors 68000
Jul 7, 2008
1,571
497
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

macrumors 6502
Nov 2, 2007
371
92
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.

It does. All the USB ports on the rear are 3.0.
Thanks for the explanation.
 
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