I recently upgraded to the M3 Max and also updated the SD card for my camera. When I tested my SD card in the built in slot it seemed rather slow so I found my old Kingston USB 3.0 SD card reader from 2016 and tested it on that and found the results to be about 10mb/s faster (read and write) on the Kingston card reader. Very odd, so I tested my old SD card that I replaced and also found the Kingston card reader to be about 5-10mb/s faster. Is this normal behavior? How is my old card reader beating out the built in slot on my MacBook? I was considering returning the SD card I just purchased for higher end V90 card but I don't see what the point is if the MacBook can't take advantage of it. I'm wondering if anyone here is using V90 SD cards advertised 300mb/s read and at least 260mb/s write and are actually getting close to those speeds. Thank You.
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M3 Max SD card slot performance
- Thread starter Miltz
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I don't have any UHS-ii SD cards yet so can't share any experience. However, I recall MacRumors reported the SDXC slot on MacBook Pro is limited to 250 MB for UHS-ii and about 90 MB/sec for UHS-i.
Another factor influencing transfer speed is file size. You get better sequential speeds when transferring large video files, for instance, compared to thousands of smaller image files.
Another factor influencing transfer speed is file size. You get better sequential speeds when transferring large video files, for instance, compared to thousands of smaller image files.
I can tell you exactly.
Software used: Black Magic Disk Speed Test, 2GB read/writes. Difficult to time the screenshot, because the "READ" stays red and it starts cycling to the "WRITE" next, so once the "READ" red circle was full and it briefly paused, I took the screenshot.
Hardware used: 14" MBP M3 Max 16/40 64GB 2TB built-in SD card reader
SD Card results for UHS-II and UHS I:
Sandisk Extreme Pro 64GB 300MB/s UHS-II: 297.7 MB/s write | 246.1 MB/s read
Sandisk Extreme Pro 128GB 170MB/s UHS-I: 89.5 MB/s write | 88.6 MB/s read
Software used: Black Magic Disk Speed Test, 2GB read/writes. Difficult to time the screenshot, because the "READ" stays red and it starts cycling to the "WRITE" next, so once the "READ" red circle was full and it briefly paused, I took the screenshot.
Hardware used: 14" MBP M3 Max 16/40 64GB 2TB built-in SD card reader
SD Card results for UHS-II and UHS I:
Sandisk Extreme Pro 64GB 300MB/s UHS-II: 297.7 MB/s write | 246.1 MB/s read
Sandisk Extreme Pro 128GB 170MB/s UHS-I: 89.5 MB/s write | 88.6 MB/s read
Thank you for this. Perhaps I should return the card I got and get the Sandisk. I got the Lexar Gold, I should be getting 280/205 and I’m getting 205/185. Very off, especially for read. Now when I actually transferred real files and used a timer I got 235 read which is closer to 280 than the 205 black magic showed.
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You're welcome. I used to be a professional photographer as part of my job until a few years ago and went through a lot of SD cards and SanDisk were always the best. I had some trouble with Lexar but that as back in the CF days. Also Sony makes some pretty good, fast SD cards. Remember, these are sustained writes with larger files, so there may be variance there. But I think that's how they rate the cards, since it includes video. Just know that the slot is capable of faster. Although when I was running 1GB files it showed higher speeds than this, but it's like it didn't get a chance to settle in, like it was more of a burst at first, so I went with 2GB which seemed more accurate.
Since you’re out of the business, any old cards or drives laying around to sell? I find they get used minimally compared to corporate environments.