 There we go. 10 gig networking on an M1 Mac mini? That's just, wow. Well, maybe. The thing is, just because a port is present on your computer doesn't mean that it will operate at full speed. And it certainly doesn't mean it will operate at full speed all the time. USB, for example, is rated by the speed that is shared across multiple ports. High speed IO and SSD slots often share resources, meaning that both of them will slow down if you use them simultaneously. And in the early days of gigabit networking, basically no motherboards could run those ports at full speed because they were connected to the lethargic PCI bus. You know, the old non-express PCI bus. Of course, we only know these things because vendors like Intel publish block diagrams of their platforms to help us understand their capabilities. Apple, on the other hand, doesn't know such thing, meaning that if there are internal bottlenecks, the only way to find out about them is to have your performance drop while you're in the middle of doing something. That makes today's adventure interesting for two reasons. One, it'll tell us if Apple delayed this version of the M1 mini, perhaps over performance concerns. And two, it might give us some fresh new insight into the black box that is Apple's M1 SoC. And it also might give us some insight into our sponsor, Honey. Honey is the free-to-use shopping tool that helps search for some of the best promo codes on lots of your favorite sites. Get it today at joinhoney.com slash LTT. The M1 Mac mini blew us away, not just with its performance, but also with its price. It beat out every previous Intel Mac in single-threaded benchmarks and a Ryzen 5 5600X, one of the fastest single-thread desktop CPUs in the market, all without breaking the bank. It didn't have the cores to back that up in heavily multi-threaded tasks, but so far that hasn't generated many, if any, user complaints thanks to M1's tight integration with macOS and of course the availability of the Mac Pro if you really need more horses. What has generated complaints is the I.O. With just two USBs, two Thunderbolt ports, and a single one gigabit ethernet jack, M1's mobile pedigree seemed to be holding it back for people like me who love the CPU performance, but need to work with heavy video footage or other shared resources over a network. If one gig wasn't enough, you had to use a bulky, expensive dongle and use up one of your Thunderbolt ports, or you had to buy into a dead end Intel platform, which was so disappointing for me personally, after seeing Apple push 10 gig forward over the last few years. First with the iMac Pro, then with the Mac Mini. But it turns out, I just didn't have enough faith. In my hand right now is a shiny new 10 gig version of the M1 Mac Mini, and we're gonna be running iPerf on it as a server to give us full control over what other ports or devices might be hogging PCI express bandwidth causing potential bottlenecks. So to start, we're running an absolute best case scenario here with nothing plugged into it other than networking and power. Not even our display. Let's come over here and have a look. That is, dang, that is pretty stable. 9.25, 9.45 gigabits per second. Not too shabby, because remember guys, 10 gigabit is the line speed, and it's perfectly normal for the actual data speed to be a bit lower. What's not normal is the price for our 40 ounce water bottles on lttstore.com. They're the same as 21 ounce. What a deal. Now let's up the ante and connect a Pro Display XDR. But, minus, you might ask, why would plugging in a monitor affect how much bandwidth is left over for something like high speed networking? I'm so glad you asked. The M1 Mac Mini is notable for being the first Mini with DSC or display stream compression. And what that does is it allows it to have enough leftover bandwidth to run the integrated USB 3 hub on this monitor at full speed. Previous Intel-based Mac Minis ended up running either not at the full 6K resolution or in an uncompressed tiled mode that some users have reported actually took this hub and knocked it all the way back to USB 2 speeds. That's because uncompressed, this monitor will suck up about 34 gigabits per second of bandwidth. To be clear, I'm not actually expecting this to throttle our network speed. It's just an excellent illustration of how a system has a finite amount of resources that needs to be carved up. Also, now that we've got our display up, you can see that the terminal on our Mini matches our SSH session. So no smoke and mirrors here, ladies and gentlemen. Well, let's go ahead and try it again, shall we? And as expected, we are exactly the same. I mean, no computer manufacturer in their right mind would rate the speed of their ports assuming that no display is plugged in, especially not a display they make, right? But we're gonna kick things up a notch. And to do so, Anthony repurposed some of a shell script that he wrote previously that constantly writes data to an SSD and then spits out speed info at regular intervals for graphing purposes. And he targeted it at this high-performance Thunderbolt SSD. Maybe with this thing running, we'll finally start to see some bandwidth sharing in our iPerf test. All right, Apple. All right. I'm impressed. Our SSD right now is pulling over 10 gigabits per second in reads, putting us darn close to the up to 40 gigabits per second number that's advertised for these ports. But all that tells us so far is that the two Thunderbolt ports don't share bandwidth. So let's continue. Remember the USB hub I mentioned on the back of the Pro Display XDR? Well, we're gonna load it up with USB-C SSDs. We're gonna run that SSD script on all three of these at the same time. Then we're gonna run our network test and see if we can make this poor Mac mini cry. And good news, sort of. Our SSDs did slow down. That means we managed to find a bottleneck. But it's in the USB hub of the Pro Display XDR which presents us with a couple of problems. Number one, that doesn't actually tell us anything about internal bottlenecks of the M1 Mac mini. And number two is we are fresh out of USB-C ports to plug SSDs into. Unless a Thunderbolt dock. Ah, yes. We need a Thunderbolt dock and more SSDs. Ha ha, ha ha. We're gonna plug all these in and then we're gonna run the script on them and then see how you like that. There we go. Five SSDs plugged into the hub. And then for good measure, an additional one, another Thunderbolt 3.1 plugged in to the Thunderbolt daisy chain. Guys, if that 10 gig ethernet is stealing bandwidth from somewhere, we are going to find it. Huh, our pre-planning did not have this actually go down at all. We figured it out. One of the disks was not showing up properly and running the command to a missing target was causing something. I don't know, maybe some kind of CPU overhead. Anyway, now that all the disks are showing up, we are getting the results we expected which is anywhere from 9.3 to 9.42 gigabit per second. And this is even with all of the drives running. The CPU usage while we're just doing this is around 18%. And that's with all the drives plugged in. If I add that drive that's not plugged in, hopefully it's not a problem. What's our CPU usage at now? 32, 36, significantly higher. Interesting. I didn't test this on the bench. I didn't expect this. Okay, it's gone. 40, 77. Okay, wow. Way to write a script that hurts computers when you do it wrong. But while our side adventure was interesting, hey, turns out runaway CPU usage is going to affect network transfer performance. It wasn't really the point of the video today. So let's refocus and talk about what we've learned so far. There's a few things actually. So one, we now know that the 10 gig M1 is legit non-shared 10 gig. No switch chips, no controller hubs, just a whole Gen 4 PCI express lane. That's why nothing that we did was able to bottleneck it. So clearly Apple's delay had nothing to do with performance and you can buy this puppy with confidence. That's cool, but we're not done. Diving deeper, while our theoretical max speed when testing the drives individually works out to just over 58 gigabits per second, it capped out somewhere around 50 in the real world. And that means that we did throttle somewhere. The SSDs connected to the Pro Display XDR were obviously going to throttle as they were being crowded by that chunky 13.7 gigabit per second display port signal. But the Thunderbolt 3 hubs throttling is another story. And this one comes primarily down to the fact that each Thunderbolt 3 port appears to be capping out at around 20 to 22 gigabits per second. But hang on a second Linus, Apple said each of these ports could do up to 40 gigabit per second. And you said they didn't share bandwidth. What gives? Okay. So remember how our 10 gig NIC is expected to be less than 10 gigabit per second in the real world? Well, the same is actually true for Thunderbolt 3, USB 4, whatever the hell this thing is. So around 7.6 gigabit per second of that is set aside for a display port, which our Thunderbolt 3 dock has. And then the rest of it gets eaten up by the signal encoding, bringing us down to a theoretical maximum of only around 26 gigabits per second. And that's close enough to our numbers that the difference probably comes down to the fact that we're going through busy hubs rather than attaching directly. Hence the wavy patterns on the graphs compared to the individual drive results. That means that if you've got applications that are sensitive to IO variants, like audio or anything involving real-time data, you would do best to directly attach or use only one high-speed device on a hub or dock at a time. Of course, for most people, this is academic and it won't make a difference in the real world. Well, sort of. Because M1 is still IO limited and it has affected the port options on Apple's M1 products. Like for example, the new iMac, which we'll be reviewing, so make sure you're subscribed. The question just becomes, how limited is it? What it looks like is we've got two PCI Express Gen4 lanes going to Apple's Thunderbolt controller, which steps down to two Thunderbolt 3 channels. Then we've got one Gen4 lane for the 10 gig NIC. There's 10 gigabits to go around for the type A ports. So that's another lane that is maybe shared with the Wi-Fi 6 adapter. And then there's an HDMI port connected directly to the GPU via an internal display port to HDMI converter. That's your IO. Four lanes accounted for. We ran the iOreg terminal command to try and find out for sure. But while it does show device hierarchies, it doesn't show how they're connected to the main system, just that they are connected. Of course, most PC systems have a lot more than four PCI Express lanes. Surely M1 does as well then, right? Well, not necessarily. You might think it would have another four lanes at least for its SSD, but it doesn't. Remember how the T2 chip that we loved so much was the storage controller for the final generation of Intel Macs, and then it just disappeared with the M1? Well, the reverse engineering effort for getting M1 running on Linux has actually discovered that Apple wasn't kidding. The M1 SoC has its security chip built right into it, and it's controlling the SSD directly through some kind of memory map arrangement, not through PCI Express. And you gotta remember, NVMe is a protocol. So while we associate it with PCI Express, it doesn't technically have to run over PCI Express. All of which is to say then that the M1 Mac mini is probably near the limits of what Apple can manage with the M1 SoC, but it's got far more iO than we initially gave it credit for. Because remember, we haven't even accounted yet for whatever bus they're using for the internal GPU. So the reason they held off on the 10 gig version was probably more to do with logistics or strategy, but whatever it was, Apple has done a lot here, with little, and that's pretty admirable. Kind of like how Apple used to be back in the good old days. And kind of like my segues to sponsors like Micro Center. Get the best prices and best selection on computer hardware and everything else technology at any one of Micro Center's 25 locations across the United States. 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