SDXC and 2015 MBP, performance? experiences?

My 512GB SSD is ham-stringing me again as my new imaging data starts to come in (3GB, 11k files per person). I’ve been down the replace-the-ssd route, and kernel panics brought me back.
I was thinking about taping (using gaffer tape, 'natch) an SSD to my laptop, but then remembered I have an SD card slot. Apple mentions that SDXC cards are support up to 4TB. I’m thinking more like 256GB or 512GB. They also mention that it is possible to install macOS or Windows on an SD card, which leads me to believe the performance would be good enough for my data analysis processes.


Apple says the SD card slot on laptops uses the USB bus, and is limited to 480Mb/s. This means that UHS-II (312Mb/s) would almost max out the bus, whereas UHS-III (624Mb/s) would definitely max it out (ref).

As these are quite spendy, I would greatly appreciate opinions and especially experiences using SD(XC) cards with a laptop.



Rather than taping a drive to my laptop, or having one rattle around in my backpack as I trek from school to home, working in both places, the SDXC card seems to fit the bill.

I have a stack of 1TB Samsung T5 SSD drives that I use for storage, cloning, etc. They are super fast, and highly reliable. I don’t like SD cards for data strorage – too easy to break, physically. The T5s come with USB C-to-C and C-to-A cables.

Thanks. I left out the portability part of my scenario above, and have edited my original post.
I have a 512GB SSD that I use for backups, which I could convert to a working drive, but I was thinking an SD card that stays in my laptop would always be available. Physical breakage risk would be minimal if it lives in my laptop.

Looks like someone thought of this a while back.