You might not know this, but Apple has given us a nice surprise in macOS Ventura and iOS by discreetly including native support for NVIDIA/Mellanox ConnectX network cards. The result? You can now boast about having a 25 Gbit/s network and more, both on your Macs and iPad Pros!
But let’s not get too excited too quickly, because to enjoy this, you’ll need to lighten your wallet and get a bit creative with the connections. However, it’s worth it if you’re a real enthusiast who loves seeing terabytes fly by at lightning speed. First, you’ll need to get a ConnectX-4, ConnectX-5, or ConnectX-6 network card. These models generally start at 25 Gbit/s with dual port SFP28 and can go up to 200 Gbit/s for the most powerful versions. Of course, it’s not cheap, but as they say, you get what you pay for. Besides, you’re presumably rolling in dough (not).
Next, you’ll need a Thunderbolt or USB4 enclosure compatible with PCIe tunneling. The hackers who set this up at Kitten Labs used an NVMe TBU401 enclosure, costing around 100 euros, which works very well. They then added a small M.2 to PCIe x4 adapter. And there you go, it’s done!
If you take the plunge, avoid cheap 30€ USB enclosures as they won’t work. They only convert USB storage to NVMe, while you need real PCIe tunneling.
Note that the NVIDIA/Mellanox ConnectX-4, 5, and 6 cards will only work with the AppleEthernetMLX5 driver included by default in recent versions of iOS/macOS. As for power, you’ll need to get a bit creative. The PCIe port provides 12V and 3.3V, while USB-C only offers 5V. Fortunately, the NVMe enclosure will convert 5V to 3.3V, but for 12V, you’ll need an external power supply. A small 12V/2.5A block should suffice to power the ConnectX card and the Thunderbolt chipset.
So, you might also wonder if you can connect an external GPU at the same time. Well, on an Intel Mac or a Windows/Linux PC, it’s no problem, but on Apple Silicon chips, don’t even think about it. Not only are there no drivers, but there’s also a hardware limitation at the memory mapping level that causes issues. Too bad, running Crysis in 8K on an M1 MacBook Air would have been nice, but you’ll have to wait. Sigh.
On to the practical part! For the bravest among you who want to try the 25 Gbit/s adventure on your Mac or iPad Pro, here’s a little tutorial. Fasten your seatbelts, it’s going to be a wild ride! 😎
There you have it! It’s not cheap, and you’ll need to get your hands dirty, but imagine the joy (I guess) of seeing your Mac or iPad displaying 25 Gbit/s effortlessly. Be careful not to overheat them, though; this hardware is still sensitive ^^. Also, remember that the maximum network speed is limited by the Thunderbolt/USB4 interface to around 40 Gbit/s. Additionally, USB-C power alone won’t be sufficient, hence the need for an external power supply.
For those interested, the blog post on kittenlabs.de provides more details, including speed tests under macOS and iOS, as well as a wealth of information for those who want to embark on the 25 Gbit/s adventure.
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