I posted this in the Mac Accessories thread but I thought it would be appropriate here too. With my M4 Mac mini, I am now using an LG UltraFine 6K monitor with built-in Thunderbolt 5 hub. I have a USB 4 / Thunderbolt SSD hooked up through the monitor and it works fine, but because the M4 is Thunderbolt 4 only, I don’t get the full write speeds since it’s sharing bandwidth with the monitor. This is not the SSD I’m using there right now, but I did do some testing with the same AS Media 2464PD enclosure using a Samsung 990 Pro SSD.
Directly connected to Mac. Drive shows as USB 4 in the macOS System Report.
Connected through TB 4 / USB 4 hub. Drive shows as Thunderbolt.
Connected thru LG 6K monitor with built-in TB 5 hub, but sharing (TB 4) bandwidth with monitor. Drives shows as USB 4.

While it would have been nice to have a TB 5 Mac mini to be able to get faster TB 4 SSD write speeds when sharing that TB connection with the monitor, the TB 4 Mac mini has been fine overall. Since the drive I’m currently using is only a Time Machine drive with small incremental updates, I don’t notice the difference at all with the slower writes. It’d make a difference with a new drive when it’s transferring everything over the first time, but in regular active use it is not noticeable.
However, I’ve now even downgraded the connection to a USB 3 cable for the time being just because I didn’t have a long enough Thunderbolt cable so the speeds would be even slower, but it still works fine and the bonus is it stays cooler since it uses less power.
Power usage and heat generation from SSD: USB 4 > TB > USB 3. That follows the speed differences.
BTW, TB 4 only supports DisplayPort 1.4 but that works fine with this LG monitor and with the Asus 6K at full 6K 10-bit HDR with 4:4:4 chroma, since they can use visually lossless DSC compression. TB 5 with DisplayPort 2.1 would support that without DSC but it’s not needed here. However, I know with some Chinese 6K monitors and the Dell 6K, there is a bug preventing DSC from working consistently, so DisplayPort 2.1 would be advantageous to have with those.
What’s the memory chip upgrade loophole?
? SSD NAND third party upgrade ?