Slow write speed to USB 3.0

Quite often I transfer large video files from HDD to a Sandisk USB stick. The sticks are NTFS and USB 3.0. The speed always starts around 140MB/s but very quickly drops to 2MB/s, occasionally increasing to 20MB/s for just a second before dropping back to 2MB/s. This happens on multiple sticks with various files. I have attached a typical speed display of a single 22GB file transfer which took over 2 hours. The HDD meter barely went above 0%. Can anyone explain why this is and what can be done to enable a constant high speed transfer?

It's the same old issue, read the data write the data. Several things could be at play such as using a USB Thumb drive in the wrong port, mixing USB 2 and USB 3. The amount of RAM can play a role as can whether the Virtual Memory/paging file/swapfile is in use and how large the setting is. I haven't checked whether changing the factory formatting of FAT32 on Thumb drives to NTFS affects the speed. Copying/Moving data from one USB drive to another seems to take a little longer than from the system drive to a Thumb drive.

Do your USB sticks have fast read/write speeds? If you have bought cheap USB sticks they may have slow read/write speeds? See photo.
The 'MyMemory' sticks are noticeably faster.

Use 'CrystalDisk Mark' to check USB stick speeds. See CrystalDiskMark

If you want a solution, here's mine. For transferring large files, chuck the usb flash drives. Either purchase an external ssd or go the poor man's route and do what I did. I took all my old ssds and m.2 sata drives and put them in usb 3.2 enclosures.... Now I've put all those unused drives to good use and have tons of fast external storage for less than $20 each. Flash drives will always have their uses but when dealing with large files, ssd is the only way to go IMO.

I just did similar, got a Sabrent housing for an NVMe 1TB drive and transferred the contents from a 1TB SATA portable HDD, much more transportable.

I don't plan on buying any more large flash drives. Extra SSDs in external enclosures are faster.

"Can anyone explain why this is and what can be done to enable a constant high speed transfer?

The limitation is the memory chips used in low cost USB sticks. You cannot just dial up the speed, that would generate heat and the chips would fail.
There are more costly USB sticks with higher speed memory chips.

Your numbers are typical for that type of a low cost USB stick. So is the initial peak which is just the system finding out the limitations.

There are newer alternatives of drives using SSD memory chips which are much faster, but again there are interface and thermal limits.

Purchases me soon as a i can Sata SSD enclosure to at least put some use my old Sata 250GB SSD for storage of a bit of files, surely will be faster than trying to store on the Flash drives lol

I too have found the large Sandisk flash drives to be terribly slow to the point i don't even bother trying to store a copy of the The Music On those drives anymore, if i can get the Drive Dock to recognize the Sata SSD shortly here, gonna use that, and if it doesn't, then soon as i get a working Gift card gonna renew Malwarebytes Premium, and also get an enclosure for the Sata drive.

This Compact Attache (64GB) flash drive is painfully slow.

Here's a 980 Pro in a NVMe Sabrent enclosure via USB C

Berton said:

It's the same old issue, read the data write the data. Several things could be at play such as using a USB Thumb drive in the wrong port, mixing USB 2 and USB 3. The amount of RAM can play a role as can whether the Virtual Memory/paging file/swapfile is in use and how large the setting is. I haven't checked whether changing the factory formatting of FAT32 on Thumb drives to NTFS affects the speed. Copying/Moving data from one USB drive to another seems to take a little longer than from the system drive to a Thumb drive.

Click to expand...

I have 32GB RAM so that's not the problem. The correct ports are in use. I'm not sure how to check swapfile. I did wonder if it was something like that that may be the problem.

wiganken said:

Do your USB sticks have fast read/write speeds? If you have bought cheap USB sticks they may have slow read/write speeds? See photo.
The 'MyMemory' sticks are noticeably faster.

Use 'CrystalDisk Mark' to check USB stick speeds. See CrystalDiskMark

View attachment 82457

Click to expand...

Even your slowest stick is several times faster than mine.

Thanks everyone for your replies. You all seem to think the speeds are normal. I thought they were too slow for SanDisk. I use sticks because they are easier to plug into other various devices such as TVs. I have a couple of external SSDs so I shall ditch the sticks.

sydh said:

I'm not sure how to check swapfile

Click to expand...

You can see the swapfile size in the root of C: drive as long as 'Hide protected operating system files' is unticked. Remember to tick it again after viewing. See photos.

I have just used USBDeview to run a speed test. As you can see, the speeds are far better than I am getting in practice so I'm sure there must be another problem somewhere.

I don't know why you are having this problem but your decision to use SSDs seems the best solution. I never use USB sticks (no matter how fast they say they are) for large file transfers. Good luck.

sydh said:

I have a couple of external SSDs so I shall ditch the sticks.

Click to expand...

sydh said:

Thanks everyone for your replies. You all seem to think the speeds are normal. I thought they were too slow for SanDisk. I use sticks because they are easier to plug into other various devices such as TVs. I have a couple of external SSDs so I shall ditch the sticks.

Click to expand...

Why would you want to ditch the sticks? They are still handy for copying small amount of data. That is what I do. I save the portable hard drives and portable SSDs when copying large amounts of data is needed.

Also, a lot of bootable diagnostic programs are made to install on a USB stick. Even Windows is best installed from a USB stick now.

I have experienced the same behaviour when transferring large files between my internal drives. The transfer will sometimes start at ~500MB/s and slow to a crawl before picking up speed once again, as shown below.



On some occasions, the copy process will slow to a complete 0MB/s stop and remain stopped for several seconds at least, before the move/copy will resume at a much slower speed.

Keep in mind, the maximum transfer speed for the average USB drive stick is ~40MB/s, so starting off at 140MB/s and then dropping is consistent with what I am seeing.

I believe it is related to Windows 11 in some way, but I am unsure just what the cause actually is and I have not found any way to correct it so far.

Of course, other programs that are often running at the same time will have some influence on the transfer speeds, but I would not say they are the cause of the problem.

I have seen similar behaviour in Windows 10 as well, but not to the same extent as Windows 11.

Strangely though, transfers to/from my NAS are relatively consistent with only minor fluctuations in speed. I am guessing the network is the difference here.

I know there have been various file transfer issues since Windows 11 was released, but they were reported as fixed.

As someone with over 100 USB flash drives (UFDs), I can tell you that there are HUGE differences between UFDs. I have several Sandisk Extreme Pro USB 3.1 256 GB drives that are supposed to be very fast - and they were when brand new. But they rapidly dropped to pitiful performance levels. Okay, not as bad as some, but a fraction of their original glory. Ironically, I have some other SanDisk Extreme UFDs, there are 128 GB and a slightly older model, and they run rings around the faster models.

What really irks me is that a lot of these flash drives have a fast interface (USB 3, 3.1, or 3.2) but the flash memory is SLOW. So the drive is going to be only as fast as the slowest item in the chain. It's kind of like taking a Yugo and dropping it on an Indy racetrack. You may have a racetrack that can support really fast speeds, but that Yogo is still going to be slower than a guy on a bicycle

One other thing to note is that there is a big difference between your typical UFD and an SSD. SSDs have far superior controllers and support such things as TRIM to keep performance levels high.

Interestingly, I just recently purchased a PNY Pro Elite V2 USB 3.2 UFD based upon the recommendations of others on this forum. This is the first very small (in physical size) UFD that I have ever encountered that seems to be a real SSD and actually supports TRIM. PNY claims write speeds up to 500 MB/s and read speeds of up to 600 MB/s, but just as some reviewers have noted, I am actually getting even BETTER performance than PNY claims. Admittedly, I only purchased this back on Dec 3, but I have been hamming the heck out of it and it shows no signs of slowing at all in spite of having now performed several TB of writes to the drive. I had been transitioning to SSDs, but I like this UFD even more than external SSDs because of the tiny form factor. I'm about to order several more

Bottom line is that there is a great variation in performance. Some drives that start out really fast become slow once all the cells have been used at least once, likely because their controllers have no provision for TRIM, so do your research carefully! It's also an example where what seems to be a good deal at a low cost may be a case of "you get what you pay for".