Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

loybond

macrumors 6502a
Original poster
On my iMac 5K (2017) my USB-C connected 1 TB NVMe drive would do 900/930 MB/s write/read on Catalina. On Big Sur, it got down to like 30 MB write speed.

I took that same drive, formatted as APFS, and connected to my M1 MacBook Air, I'm getting 15 MB/s writes. Best read is 500 or so. Anyone else experiencing this?
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.