iPad External memory Read/Write speeds with iPad Pros (2020) and iPad Air 4

[ilovejedd]

Originally Posted by OtinG

I think they are so small they have heating issues. They have a limited amount of surface area from which to dissipate the heat adequately. The really small ones are even worse. The Samsung 64GB I tested almost completely disappears when plugged into a USB port on my MacBook Pro. Only about 1/4” sticks out and that partion is plastic. It gets extremely hot. It runs much cooler though when using an adapter cable with my iPad Air 2020. That is probably because the adapter cable port is completely exposed allowing more heat dissipation.

I reformatted the two flash drives I tested to APFS. They both ran about twice as fast with APFS as they did with exFAT. But they both ran way slower on the iPad than on the Mac, and on the ipad they never got near the theoretical top speed for USB 3.0 on a flash drive, which seems to 150MB/s. One got close with 123MB/s on the Mac though.

Heat isn't really the issue (unless you've been stressing the drive for a long time). You need a good controller and parallelism to hit high speeds. Unfortunately, flash drives usually have neither. Heck, there are plenty of USB3 flash drives that are slower than USB2 HDDs (~40MB/s read/write). I have the same Samsung Fit flash drive. It's just not particularly fast, iirc.

Mind, even on SSDs, once you've run out of pseudo-SLC cache on modern SSDs, 256GB usually have significantly lower write speeds compared to, say, 1TB.

On Windows, I think USB3 tends to top out at ~300MB/s while UASP allows up to ~500MB/s.

I tested a freshly initialized Crucial MX500 2TB with, iirc, a Rosewill USB3-SATA adapter with UASP support. Used this USB-C hub to get USB-A ports.

https://www.amazon.com/uni-USB-Hub-6...dp/B07Q8TRVTN/

Test data is 13.06GB, 51 files. 4 are MP4 movies that are ~3+ GB each. The rest of the files are metadata and artwork (poster, backgrounds, etc).


2020 M1 MacBook Air 8GB/512GB

Crucial MX500 2TB
Read: 302.7 MB/s
Write: 315.3 MB/s


2020 iPad Pro 12.9 256GB

Crucial MX500 2TB
Read: 216.9 MB/s
Write: 166.3 MB/s

I'll add results for the 2017 iPad Pro 12.9 when I find the Lightning-USB3 Camera Adapter.

[OtinG]

Originally Posted by ilovejedd

Heat isn't really the issue (unless you've been stressing the drive for a long time). You need a good controller and parallelism to hit high speeds. Unfortunately, flash drives usually have neither. Heck, there are plenty of USB3 flash drives that are slower than USB2 HDDs (~40MB/s read/write). I have the same Samsung Fit flash drive. It's just not particularly fast, iirc.

Mind, even on SSDs, once you've run out of pseudo-SLC cache on modern SSDs, 256GB usually have significantly lower write speeds compared to, say, 1TB.

On Windows, I think USB3 tends to top out at ~300MB/s while UASP allows up to ~500MB/s.

I tested a freshly initialized Crucial MX500 2TB with, iirc, a Rosewill USB3-SATA adapter with UASP support. Used this USB-C hub to get USB-A ports.

https://www.amazon.com/uni-USB-Hub-6...dp/B07Q8TRVTN/

Test data is 13.06GB, 51 files. 4 are MP4 movies that are ~3+ GB each. The rest of the files are metadata and artwork (poster, backgrounds, etc).


2020 M1 MacBook Air 8GB/512GB

Crucial MX500 2TB
Read: 302.7 MB/s
Write: 315.3 MB/s


2020 iPad Pro 12.9 256GB

Crucial MX500 2TB
Read: 216.9 MB/s
Write: 166.3 MB/s

I'll add results for the 2017 iPad Pro 12.9 when I find the Lightning-USB3 Camera Adapter.

Thanks for the report! Those are very good speeds. The 2020 M1 MacBook Air has a Thunderbolt 3 (USB 4) port capable of up to 5000MB/s. The 2020 iPad Pro 12.9 has a USB 3.1 gen 2 port capable of 1250 MB/s. Both are impressive speeds.

The WRITE speeds with your 2020 iPad Pro 12.9 are twice as fast as those with my MacBook Pro and the SanDisk 250GB SSD, although the READ speeds are much slower. I got 428 MB/s READ and and 89 MB/s WRITE, but the same SSD on my iPad Air 2020 only had 112 MB/s READ and 17 MB/s WRITE so it got left in the dust on that test. But like you said, the larger capacity the SSD or flash drive, the higher the "up to" speeds claimed by the manufacturers. I assume that up to a certain point, the faster the USB port on a Mac or iPad will result in faster READ/WRITE speeds from the connected storage device as well. A faster port probably won't help much or any with an older USB 2 device, but hopefully it would help a bit with USB 3 drives.

I'm very impressed with your Crucial MX500 2TB. It obtains 3.5x faster WRITE speeds on your M1 Mac Air than my SanDisk 256GB SSD does on my MacBook Pro. At 89 MB/s, the SanDisk SSD is really a bit too slow for me to process Lightroom files directly off of it. I can do it, but it noticeably slows down the processing and gets rather laggy at times. But with 300 MB/s WRITE speeds I doubt it would be as noticeable, if at all. Unfortunately, the iPad Air 2020 with Lightroom app won't allow processing of externally stored files. The app or the iPad prevents this, either way it means I have to first move the files to the iPad then process them thereon before returning them to the external storage drive. But that Crucial MX500 2TB on my older MacBook Pro would likely allow me to process Lightroom files directly from it, and that in itself would save me a lot of time. Just copying 30 GB of RAW files to and from my SanDisk SSD takes several minutes.

[OtinG]

Originally Posted by ilovejedd

.... I tested a freshly initialized Crucial MX500 2TB with, iirc, a Rosewill USB3-SATA adapter with UASP support....

Is this the SSD you have?

And is this or this the kind of SATA to USB adapter you used?

And lastly, which format would you use, APFS?

I would like to get something like that for my MacBook Pro 2014 because it has only a 250GB internal SSD. I don’t want to mess with having that replaced with a larger one. I'm of the thought that if it works don't mess with it! But I would like an external SSD fast enough to process Lightroom galleries and video directly from it. I'm currently using the SanDisk mentioned in earlier posts, but it is only 250GB and too slow. I don't care about portability as this drive would remain with my MacBook Pro all the time. The portable SSD drives at 2TB cost considerably more than the ones like you have.

Basically, I want to extend out the usefulness of my old MacBook Pro for a couple more years or so. Plus you can never have too many backup drives.

[ilovejedd]

Originally Posted by OtinG

Thanks for the report! Those are very good speeds. The 2020 M1 MacBook Air has a Thunderbolt 3 (USB 4) port capable of up to 5000MB/s. The 2020 iPad Pro 12.9 has a USB 3.1 gen 2 port capable of 1250 MB/s. Both are impressive speeds.

The WRITE speeds with your 2020 iPad Pro 12.9 are twice as fast as those with my MacBook Pro and the SanDisk 250GB SSD, although the READ speeds are much slower. I got 428 MB/s READ and and 89 MB/s WRITE, but the same SSD on my iPad Air 2020 only had 112 MB/s READ and 17 MB/s WRITE so it got left in the dust on that test. But like you said, the larger capacity the SSD or flash drive, the higher the "up to" speeds claimed by the manufacturers. I assume that up to a certain point, the faster the USB port on a Mac or iPad will result in faster READ/WRITE speeds from the connected storage device as well. A faster port probably won't help much or any with an older USB 2 device, but hopefully it would help a bit with USB 3 drives.

I'm very impressed with your Crucial MX500 2TB. It obtains 3.5x faster WRITE speeds on your M1 Mac Air than my SanDisk 256GB SSD does on my MacBook Pro. At 89 MB/s, the SanDisk SSD is really a bit too slow for me to process Lightroom files directly off of it. I can do it, but it noticeably slows down the processing and gets rather laggy at times. But with 300 MB/s WRITE speeds I doubt it would be as noticeable, if at all. Unfortunately, the iPad Air 2020 with Lightroom app won't allow processing of externally stored files. The app or the iPad prevents this, either way it means I have to first move the files to the iPad then process them thereon before returning them to the external storage drive. But that Crucial MX500 2TB on my older MacBook Pro would likely allow me to process Lightroom files directly from it, and that in itself would save me a lot of time. Just copying 30 GB of RAW files to and from my SanDisk SSD takes several minutes.

Keep in mind I had the Crucial formatted as APFS.

Chances are your SanDisk SSD may be capable of better write speeds on both Mac and iPad. The question is are you willing to reformat it to APFS?

Mind, the larger the capacity of the SSD or flash drive, the higher the chances of those actually meeting the manufacturer's "up-to" speed since these basically function like internal RAID-0. Unless, of course, the manufacturer is simply quoting theoretical bus speeds. There's always some real-world losses so you never really get that.

Originally Posted by OtinG

Is this the SSD you have?

And is this or this the kind of SATA to USB adapter you used?

And lastly, which format would you use, APFS?

I would like to get something like that for my MacBook Pro 2014 because it has only a 250GB internal SSD. I don’t want to mess with having that replaced with a larger one. I'm of the thought that if it works don't mess with it! But I would like an external SSD fast enough to process Lightroom galleries and video directly from it. I'm currently using the SanDisk mentioned in earlier posts, but it is only 250GB and too slow. I don't care about portability as this drive would remain with my MacBook Pro all the time. The portable SSD drives at 2TB cost considerably more than the ones like you have.

Basically, I want to extend out the usefulness of my old MacBook Pro for a couple more years or so. Plus you can never have too many backup drives.

The BX500 is a cheaper version that doesn't have DRAM, I believe. You'll have to check out the reviews for that one to see how performance compares. I seem to recall thinking that price was too close to SSDs with DRAM to make it worth the performance inconsistencies.

The MX500 is the drive I tested ($210 right now but got it for $185 on sale during World Backup Day or something):
2TB: https://smile.amazon.com/dp/B078C515QL/

I believe the WD Blue 3D is pretty much the same drive but goes on sale more often and is slightly cheaper at the moment.
2TB: https://smile.amazon.com/Blue-NAND-2...dp/B073SBRHH6/

This is the adapter I used:
https://smile.amazon.com/Rosewill-Ad...dp/B06WVDK9QD/

You might also want to consider the Samsung T5 (SATA-based) so you won't need to buy a separate USB3/C-SATA adapter.
1TB: https://smile.amazon.com/Samsung-T5-...dp/B073H552FJ/
2TB: https://smile.amazon.com/Samsung-T5-...dp/B073H4GPLQ/

The Samsung T7 (PCIe-based) is pricier per GB but offers faster performance:
1TB: https://smile.amazon.com/SAMSUNG-Por...dp/B0874YJP92/

Errata: It's the SanDisk Ultra and WD Blue 3D that are similar. MX500 uses different controller and NAND, I believe. Mind, performance is pretty similar on all the high-end 3D TLC SATA SSDs (Samsung 860 EVO, Crucial MX500, WD Blue 3D) anyway so I usually just grab whichever one's on sale.

[OtinG]

Thanks for all the information!

I'm going to reformat my SanDisk 256GB SSD to APFS and use it with my iPad Air 2020. It is too small a capacity for what I want with my MacBook Pro. I want to get a good 1TB to 2TB SSD drive for it so that I have plenty of storage.

ETA: I reformatted the SanDisk 256GB SSD to APFS. The speed connected with my MacBook Pro was slightly less, but with my iPad Air 2020 it tripled the WRITE speed and significantly increased the READ speed by about 50%.

I tested a new SanDisk 128GB USB-C USB 3.1 flash drive. I first tested it with exFat, then reformatted it with APFS. The tests have been added to the first post in this thread. It has good READ speed, but the WRITE speed is terrible at only 2.8 MB/s. I’m disappointed in this one and feel like I wasted $20.

[OtinG]

Originally Posted by ilovejedd

....I tested a freshly initialized Crucial MX500 2TB with, iirc, a Rosewill USB3-SATA adapter with UASP support. Used this USB-C hub to get USB-A ports.

https://www.amazon.com/uni-USB-Hub-6...dp/B07Q8TRVTN/

Test data is 13.06GB, 51 files. 4 are MP4 movies that are ~3+ GB each. The rest of the files are metadata and artwork (poster, backgrounds, etc).

2020 M1 MacBook Air 8GB/512GB

Crucial MX500 2TB
Read: 302.7 MB/s
Write: 315.3 MB/s


2020 iPad Pro 12.9 256GB

Crucial MX500 2TB
Read: 216.9 MB/s
Write: 166.3 MB/s

I took your advice and got a Samsung T5 2TB USB-C 3.1 Gen 2 external SSD Drive. The following tests were right out of the box with ExFAT formatting. Wow, it is quite impressive on both my 2014 MacBook Pro and iPad Air 2020!

I'm trying to decide whether to leave the Samsung T5 with ExFAT or reformat it to APFS. I'm leaning toward leaving it "as is" with ExFAT because the speeds are already impressive, and I do have a Windows 10 laptop I occasionally use. However, I do have other external drives I could use to exchange files between the Mac and the Win 10 laptop. I rarely exchange files between them though.

Once again the test file was a 1.07GB .mov video file created using a command line in the Terminal app on my MacBook Pro. However, I also included the results from the Blackmagicdesign app and the ATTO Disk Benchmark app for the MacBook Pro speeds.

IPad Air 4 with Samsung T5 2TB USB-C 3.1 Gen 2 External SSD Drive (ExFAT format)

• READ speed = 214 MB/s
• WRITE speed = 134 MB/s

MacBook Pro with Samsung T5 2TB USB-C 3.1 Gen 2 External SSD Drive (ExFAT format)

• READ speed = 357 MB/s
• WRITE speed = 356 MB/s
• Blackmagicdesign: READ = 421 MB/s
• Blackmagicdesign: WRITE = 418 MB/s
• ATTO Disk Benchmark: READ speed = 419 MB/s
• ATTO Disk Benchmark: WRITE speed = 435 MB/s

[ilovejedd]

Beware of potential corruption issues with exFAT if used with the Files app.

https://forums.macrumors.com/threads...orage.2235171/

[OtinG]

Originally Posted by ilovejedd

Beware of potential corruption issues with exFAT if used with the Files app.

https://forums.macrumors.com/threads...orage.2235171/

Very good point. I will reformat it to APFS. After all I will not need it for my Win 10 Laptop or for sharing files with non-Mac users. I've got plenty of other drives for that. And of course I now remember you said that in an earlier post. My memory retention isn't what it used to be!

ETA: I have reformatted the new Samsung T5 to APFS. As always the test file was a 1.07GB .mov video file created using a command line in the Terminal app on my MacBook Pro. However, I also included the results from the Blackmagicdesign app and the ATTO Disk Benchmark app for the MacBook Pro speeds. Here are the results from the APFS and ExFAT tests. The WRITE speed using the iPad Air 2020 was significantly increased, but the other tests were about what they were with ExFAT.

IPad Air 4 with Samsung T5 2TB USB-C 3.1 Gen 2 External SSD Drive (APFS format)

• READ speed = 195 MB/s
• WRITE speed = 195 MB/s

IPad Air 4 with Samsung T5 2TB USB-C 3.1 Gen 2 External SSD Drive (ExFAT format)

• READ speed = 214 MB/s
• WRITE speed = 134 MB/s

MacBook Pro with Samsung T5 2TB USB-C 3.1 Gen 2 External SSD Drive (APFS format)

• READ speed = 357 MB/s
• WRITE speed = 357 MB/s
• Blackmagicdesign: READ = 426 MB/s
• Blackmagicdesign: WRITE = 417 MB/s
• ATTO Disk Benchmark: READ speed = 419 MB/s
• ATTO Disk Benchmark: WRITE speed = 435 MB/s

MacBook Pro with Samsung T5 2TB USB-C 3.1 Gen 2 External SSD Drive (ExFAT format)

• READ speed = 357 MB/s
• WRITE speed = 356 MB/s
• Blackmagicdesign: READ = 421 MB/s
• Blackmagicdesign: WRITE = 418 MB/s
• ATTO Disk Benchmark: READ speed = 419 MB/s
• ATTO Disk Benchmark: WRITE speed = 435 MB/s

[OtinG]

I created a small chart illustrating the transfer speeds I was able to get between my iPad Air 2020 and seven different memory storage devices. (See the attached image.) Red represents READ speeds and black represents WRITE speeds.

The fastest READ/WRITE speeds I recorded were approximately 30% as fast as the theoretical “up to” speed for the USB-C Gen 1 port used by the iPad Air 2020. The same drive recorded READ/WRITE speeds nearly twice that fast when used with my MacBook Pro which has USB 3.0 ports and an internal SSD. I assume the iPad Air 2020 has slower internal memory than my MacBook Pro and/or that iPadOS is slower than macOS. The newer iPad Pro M1 models should get faster READ/WRITE speeds than my iPad Air 2020.

This will certainly sound a bit like Captain Obvious speaking, but here are a few generalized observations.

• For the fastest READ/WRITE speeds use an external SSD drive.
• WRITE speeds tend to be way slower than READ speeds.
• The faster the port types the faster the speeds. USB 3.1 Gen 2 is better than USB 3.1 Gen 1 or USB 3.0, especially for WRITE speed.
• USB 2 is too slow, so don’t waste your time (pun intended) with it.
• APFS is faster than ExFAT, so if possible reformat the storage device to APFS.
• Samsung drives seemed to be faster than SanDisk drives in my tests. YMMV.