Unreliable 10 Gbe with my new Mac Studio

"energy efficient" drops power to the Ethernet chip to save energy. It is NOT compatible with Top Speed.

10GB Ethernet:

The Mac Studio has a 10GB Ethernet port. If you have some fancy equipment at the other end of the cable, it is possible it is trying to make a 10GB connection.

A 10GB (or 5GB or 2.5GB) connection is only stable when cables are excellent and fairly short (like Category-6 rated cables under 100 feet). If either of those are not true, or you have you added patch cables that are not Category-6 rated, you could be seeing it connect at a faster-than-Gigabit speed, then error out and disconnect.

Actual Speed:

The good way to check the actual connection speed USED to be Network Utility, But in Big Sur and later, Apple has deprecated network Utility and now you have to use a Terminal command to see your actual connection speed. First, you need to know what en number the link is. then you use a command like this one, substituting the actual en number.

my main Ethernet connection uses BSD name en5 (as shown in) :

 menu > about this Mac > (system report) > network:

 ifconfig en5 | grep media

with this as my output:

media: autoselect (10Gbase-T <full-duplex,flow-control>)

For Gigabit Ethernet, you should get this instead:

media: 1000baseT <full-duplex,flow-control>

Errors detected:

To see if an Ethernet link is throwing more than a handful of initial errors, you can use Terminal command:

netstat -I en5

This is the resulting output. Counters are In-packets, In-errors, Out-packets, Out-Errors, Collisions. There should never be more than handful of errors from starting up, and in most cases, NONE.

Name       Mtu   Network       Address            Ipkts Ierrs    Opkts Oerrs  Coll

en5   8163  <Link#4>    00:01:d2:1a:00:dd   696697     0   484301     0     0

en5   8163  grantsmacpr fe80:4::461:ea0d:   696697     -   484301     -     -

en5   8163  192.168.0/23  192.168.0.204     696697     -   484301     -     -

If the link were running beyond its ability to run and be stable, for example it auto-speeded to 10GB but the cabling could only reliably support 2.5GB, we would see non-zero errors counts, and errors increasing over time. (and possibly, disconnecting)

Setting the link speed to Automatic has historically provided NO feedback whatsoever about actual Link speed. That System preferences grayed out information is newly added, and not available in slightly older MacOS. Its accuracy is untested and unknown.

If system preferences is the only indication of changing speeds, I would not count on its being correct.

Your switch claims to be a 'managed' switch. I hate the term, but it tends to mean a smart device that can provide statistics like errors and link speeds easily. (Enter its IP address and log in to get access to that stuff.) It should also be reporting actual 10G speeds and no errors.

¿are you seeing 10G bits/sec connection speed consistently, with no more than a handful of errors at startup, and NO accumulating errors once established?

Some users have encountered issue using very new equipment that is IPv6 capable. The problem is that it may be trying to make BOTH IPv4 and IPv6 connections at the same time.

I recommend that on your Mac, you set IPv6 to 'Link-local only'

This allows Mac Discovery protocol to discover Servers and Printers and such, but does not try to use IPv6 for data.

I had the same problem.

Changing to "full duplex, flow-control" fixed my issues.

It looks like full 10gb ethernet does not work well with slower connections without changing the settings.

Apple tech support needs to be made aware of this. Knowing this will save a lot of frustration with people having this problem.

Before discovering this solution I called support a few times. The determined my unit was faulty and issued a refund. When they received my return instead of sending my replacement they cancelled it. This is the first time I have had any problems with Apple. I purchased a new Mac Studio and changed to "full duplex, flow-control" and so far I have not had any issues.

Thanks for your help with this issue.

There is another potential diabolical issue with really fast ethernet.

It sometimes runs out of block numbers, and has to stop and wait for a group ack from the adjoining device before it can proceed.

The accommodation is to increase the allowable maximum size of the blocks, shown on the Hardware pane as MTU. The Mac itself can't go much above 8163 without changing some internal settings.You can try modestly larger, like 2x 1500 or around 3000, or even larger, and speeds may modestly improve.

Most devices can support modestly higher block sizes without issue, but some, like ISP-provided Routers, can not. if it gets a block that is too large, it will reject that black and tell the sender, "'make it smaller".

Another downside of going larger is that the checksum is covering a larger block, and if you have errors, you toss out a much larger unusable block, so this only works when your link is well-behaved already.

You mentioned disabling wi-Fi, which can be inconvenient.

Instead, use the gear icon below the list of interfaces to "set service order" then drag 10Gigabit Ethernet to the top.

Packets going to the Internet are sent to the TOPMOST, working interface in that list. Once Wi-Fi is not TOPMOST, it will not be used for Internet traffic, unless Ethernet is not Working.

Your NAS should have a private, local IP address, so its packets do not go through the Router section of your Router, they can and will be switched locally.

Generally each of these devices: {Mac, switch ports, and NAS} can and will 'autospeed', unless you tell it to use a fixed speed. If you specify a fixed speed and it cannot make a stable connection that that specified speed, it will generally make NO connection, which you will quickly find and try to fix.

The usual reason it can't make a stable connection at a specified speed is link errors, which is why I mentioned Mac error counters earlier, and we have now chatted about Switch error counters (I expect there are also NAS error counters, but that part seems to be working.)

The other reason is Mac "power saving" which turns off the high-powered devices and turns them back on when it thinks you might have been sending it something. You said you had turned power saving OFF, which is the way to run for maximum performance.

Agustis88 wrote:

It my assumption that the "automatic link speed" was the same as running ifconfig en0 | media. It could be different. From the Ubiquiti managed dashboard, I also see the link speed is sometimes reporting as 5 Gbe, and then sometimes at 10 Gbe (where the NAS is always reporting at 10 Gbe).

ATM, I experiencing 650Mbps write and when I run netstat -l en0 I don't see any errors. I also ran another Blackmagic Speed Test and monitored with netstat and it didn't report errors. Next time it drops below 5Gbps I will run netstat while running the speed test.

The principle used by Switches is 'Store and Forward'. For each received packet, the ENTIRE packet will be received, its checksum checked for packet integrity, and then (if good) forwarded to the next device.

There is no ONE link speed that can be checked here -- you need to be checking Mac to Switch, and separately Switch to NAS, for both speeds and error accumulated.

It is possible to run mismatched speeds. Throughput can be somewhat lower, but it does not go bonkers. (You are likely running mismatched speeds when talking to your Router.)

I think I suggested that in my first response to your initial post:

"energy efficient" drops power to the Ethernet chip to save energy. It is NOT compatible with Top Speed.

If you are offended by this method of response, please contact Apple support and talk to employees on the Apple payroll (charges may apply).

yes, You said you were using high quality cables.

In my reply I noted they also needed to be SHORT of the maximum length allowed by the earlier Ethernet specs.

In addition, I pointed out that use of patch panels with or without substandard patch cables could wreck your performance.

In addition, I showed you how to measure ACTUAL connection speed.

in addition, I pointed out how to tell whether you were getting link errors or not.

In addition, I articulated that energy saving and maximum speed were incompatible.

>> That adds up to a LIST of suggestions. If you feel somehow cheated that as a Volunteer I did not adequately address your personal individual situation, post back with more specific questions and maybe we can continue to help you make progress.