I'm sorry if this has been posted before but I am not sure what is the best adapter to connect my peripherals to the new 24" iMac (Two Thunderbolt / USB 4 ports - Two USB 3 ports). I currently have a 27" late 2015 iMac and I have peripherals connected using USB 2.0 and USB 3.0 ports and a screen connected via HDMI. I also use the USB lightning cable to charge my watch and trackpad so I will need to be able to charge those on the M1 iMac too.
For USB 3.1 gen 2:
The USB-only ports of the M1 iMac are faster for USB than the Thunderbolt ports because they use a ASMedia 3142 USB controller (10 Gbps over PCIe).
The next fastest USB ports may be the Thunderbolt port of a Thunderbolt 3 dock because it uses the USB controller of the Thunderbolt controller (10 Gbps over Thunderbolt).
The third fastest USB port may be the 10 Gbps port of a Thunderbolt 3 dock because it's an ASMedia 1142 USB controller (limited to 8 Gbps).
The fourth fastest USB port may be the Thunderbolt port of the M1 iMac because it uses the USB controller of the M1 chip.
The fifth fastest USB port may be the Thunderbolt port of a Thunderbolt 4 dock connected to a M1 iMac because it uses the USB controller of the M1 chip tunnelled over Thunderbolt.
I might be wrong about the ASMedia ASM1142 being better than the fourth and fifth option. I'ld have to search for the benchmarks to be sure.
For USB 3.0:
USB 5 Gbps from the USB controller of the M1 is slower than from other USB 10 Gbps controllers. I'm not sure how it compares to 5 Gbps from USB 3.0 controllers.
For USB 2.0:
Doesn't matter. You're not using USB 2.0 for the speed.
What kind of screen do you have? If it has a DisplayPort input then you should use that connected to a Thunderbolt port because DisplayPort 1.2 has more bandwidth than HDMI 2.0. If you have an HDMI 2.1 display then stick with HDMI but use a USB-C to HDMI 2.1 adapter to make sure you're getting the benefit of HDMI 2.1.
Looks like I'm gonna have to get a few of adapters. Would a hub make more sense in my case instead of buying separate adaptors?
How many devices? Since you have Thunderbolt ports, you should get a Thunderbolt dock.
- A Thunderbolt 3 dock with Alpine Ridge may have multiple USB controllers so it could have more bandwidth (but the USB controller of the Thunderbolt port will be better than the others). It may have a PCIe Ethernet adapter. Alpine Ridge only supports DisplayPort 1.2.
- A Thunderbolt 3 dock with Titan Ridge probably has only one USB controller and a couple USB hubs (but at least the hubs will be connected to the best USB controller). The Ethernet port will be provided by a USB adapter. It probably won't include PCIe devices so that the dock remains compatible with non Thunderbolt hosts. Titan Ridge can support DisplayPort 1.4.
- A Thunderbolt 4 dock/hub will be similar to that but it will have multiple downstream Thunderbolt ports. When connected to a USB4 host such as an M1 Mac, the inferior USB controller of the M1 Mac is used instead of the USB controller of the Thunderbolt 4 dock.
- A USB-C dock will be USB only and the display bandwidth will be one quarter of Thunderbolt. It will be sufficient only for displays smaller than 4K but at least it is less expensive than Thunderbolt. You can connect it to a Thunderbolt port if you want to use the display feature of the USB dock - or you can connect it to a USB port of the M1 iMac so the USB has more performance (but the display feature of the USB-C dock won't be usable).