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8 USB-A ports off a base M4 Mac Mini

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seggy

macrumors 6502a
Original poster
Feb 13, 2016
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I'm looking to get at least 8 A ports hanging off a Mac Mini, and I'd like to do it in a financially sensible way (i.e. I could daisychain a TB4+3 dock with 4 A ports each, but that would be insanity if all I want is the A ports).

They need to be 4x 2.0 and 4x 3.0 minimum, with a couple of those 3.0 ports needed to go full speed all the time simultaneously. All USB ports will need to supply the correct bus power. The Mac in question will have one of the rear ports used. Front is clear.

Any ideas?
 
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@seggy If you want "full speed all the time simultaneously" and "All USB ports will need to supply the correct bus power" then it is far from insanity to go with a TB3 dock.

You will get trouble free performance. with no unexpected disconnects...
Using a USB hub is likely to fail in one way or another - bus power or simultaneous speeds, not to mention instability during sleep. All the ports share the same 10Gbps bandwidth.

Look at the Caldigit TS3 Plus dock, which has 5 USB-A and 3 more USB-C ports , and use USB-C to USB-A adapters to give 8 USB-A sockets.

More recent TB3 docks don't have so many USB-A port, and the advantage of using TB3 is that the dock has controllers for all the USB ports on it.
With USB hubs the USB controller is in the Mac, so is reliant on the CPU for reliable uninterrupted operation.
While that is not a problem with Apple Silicon Macs, it does mean that using a TB3 dock, the CPU is no longer involved in the actual allocation of data moment by moment.
The TB3 dock's controller does this, with direct high bandwidth PCIe communication with the Mac.

Later TB4 docks don't work in this way, with the Mac's USB controller still in charge.
So they don't give any advantage preventing unexpected problems with SSDs.
 
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Sounds like you are talking about using a new M4 Mac mini.
What kind of devices do you need full speed all the time simultaneously? Some kind of video capture?

A 10 Gbps USB hub might allow two 5 Gbps USB devices to go full speed simultaneously if no other 3.0 devices are using bandwidth. Needs testing.
10 Gbps USB is actually 9.7 Gbps of data. 5 Gbps USB is actually 4 Gbps of data.
USB 2.0 devices are on a different bus than USB 3.x devices so they shouldn't interfere.

Many Alpine Ridge based Thunderbolt 3 docks like the TS3+ have two separate USB 3.0 buses (Fresco Logic FL1100). The TS3+ also has a USB 3.1 gen 2 bus (ASMedia ASM1142) where one port is USB 3.1 gen 2 and the other port is USB 3.0 which is slightly faster than the USB 3.0 ports of the FL1100. The downstream Thunderbolt port of a Thunderbolt 3 dock is also a USB 3.1 gen 2 bus (from Intel Thunderbolt controller which is slightly faster than the USB 3.1 gen 2 port of the ASM1142).
https://www.caldigit.com/ts3-plus-interface-bandwidth-allocation-and-diagram/

4 + 4 + 7.9 + 9.7 = 25.6 Gbps but Thunderbolt data is limited to ≈22 Gbps. There's no way to guarantee that devices on other ports won't interfere with full performance of a subset of ports unless the total bandwidth is < 22 Gbps.

Newer Titan Ridge based Thunderbolt 3 docks usually use a single USB bus with chained USB hubs like Thunderbolt 4/5.
 
PaulD-UK said:
@seggy If you want "full speed all the time simultaneously" and "All USB ports will need to supply the correct bus power" then it is far from insanity to go with a TB3 dock.

You will get trouble free performance. with no unexpected disconnects...
Using a USB hub is likely to fail in one way or another - bus power or simultaneous speeds, not to mention instability during sleep. All the ports share the same 10Gbps bandwidth.

Look at the Caldigit TS3 Plus dock, which has 5 USB-A and 3 more USB-C ports , and use USB-C to USB-A adapters to give 8 USB-A sockets.

More recent TB3 docks don't have so many USB-A port, and the advantage of using TB3 is that the dock has controllers for all the USB ports on it.
With USB hubs the USB controller is in the Mac, so is reliant on the CPU for reliable uninterrupted operation.
While that is not a problem with Apple Silicon Macs, it does mean that using a TB3 dock, the CPU is no longer involved in the actual allocation of data moment by moment.
The TB3 dock's controller does this, with direct high bandwidth PCIe communication with the Mac.

Later TB4 docks don't work in this way, with the Mac's USB controller still in charge.
So they don't give any advantage preventing unexpected problems with SSDs.
Click to expand...

It's better than two docks, but still way too expensive to just get a bunch of USB ports.

I was thinking two USB hubs, maybe with external power capability, but couldn't find any all-A hubs.
 
OP:

I, too, suggest the CalDigit TS3 Plus.

Go on ebay.
You can find used TS3 Plus docks in good condition for less than $100.

This is "the way you want to go"...
 
Fishrrman said:
OP:

I, too, suggest the CalDigit TS3 Plus.

Go on ebay.
You can find used TS3 Plus docks in good condition for less than $100.

This is "the way you want to go"...
Click to expand...
HMMMMM

I see some in that range, with non-original PSU and accessories. If it works, quite tempting.

But I typically never buy used (except for homes and cars) because of the way other people treat things - the only exception I make is buying used from Japan. When I write mint in the description, I mean unboxed and unused. When people here say mint, they mean lightly mauled by a chain-smoking tiger with mange.
 
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OP:

If you want "full speed" from the USB ports simultaneously, the WORST MISTAKE you will make is buying a USBc (NON-thunderbolt) hub. You won't get those speeds.

You need a thunderbolt hub, I think tbolt3 might actually be the best, for reasons explained above.

I recommend that you DO NOT buy a Caldigit TS3 Plus UNLESS it has the original power supply.
May cost a little more.
Pay the price.
You won't regret doing this.
 
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Fishrrman said:
OP:

If you want "full speed" from the USB ports simultaneously, the WORST MISTAKE you will make is buying a USBc (NON-thunderbolt) hub. You won't get those speeds.

You need a thunderbolt hub, I think tbolt3 might actually be the best, for reasons explained above.

I recommend that you DO NOT buy a Caldigit TS3 Plus UNLESS it has the original power supply.
May cost a little more.
Pay the price.
You won't regret doing this.
Click to expand...
I said I only need sustained full speed from two ports out of the 4 3.0 ports I need. I am NOT interested in a TB dock unless it's ~$100 (new), especially as I'd ONLY be using it's USB ports.
 
"I said I only need sustained full speed from two ports out of the 4 3.0 ports I need."

In that case it would need two 4 port hubs with one of those 'full speed' devices connected to each hub, and each hub plugged into a separate 10Gbps (or higher) port on the Mac mini.

If you get a big 8 port hub, connected to just one 10Gbps Mac port, then you would have to find out how the internal hub topology is played out, and then connect the two 'full speed' devices to ports that get the highest bandwidth - which will depend on how the internal hub-chip(s) is/are interconnected.

Since the cheapest hub controllers feed 4 outputs then a 7 port hub is two of these 4 port chips with the second one being fed from the first.
To get 8 outputs you are going to need a more expensive controller chip (or three of the 4 port ones).
If you plug into any of the daisy-chained secondary hub chips, then bandwidth is likely to drop.

Older Thunderbolt 3 docks like the Caldigit TS3+ (with Intel's Alpine Ridge controller) are simpler. All the output ports get ~full bandwidth because there is 40Gbps to share around.
 
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You could just use a powered USB hub with both 2.0 and 3.0 ports. Make sure it's powered so it can handle the bus power. Plugging it into the front port on your Mac Mini should give you all the A ports you need without messing with a complicated docking station.
 
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