# Sudden loss of write speed on flashdrive



## 69Rixter (Feb 26, 2018)

Recently, I noticed the write speed of a Kingston DT101G2 16Gb dropped considerably. One time it ran @ 5.5+Mb/s the, next time @ 1.8-2.3Mb/s.(using Win7) I checked my other "drives" and found 5 that have the same problem. This seems to be a rather common occurrence among flashdrives, and after going through many, many forums, the net and articles, I have not found a definitive explanation, nor a common "cure" to this anomaly. My limited knowledge has led me to question the "gate"(I hope that's the correct term) of the drive. But, that's just _my_ guess. Could someone head me in the right direction of understanding what would cause the sudden slow write speed and what I may be able to do in order to restore the drives to their original write speeds. I've done an extraordinary amount of tests on the drives and all the tests have concluded the drives are operating correctly with no "defects" detected (healthy). On the Kingston I've also wiped/rebuilt partition, formatted in both NTFS & Fat 32, tried a formatting tool directly from Kingston Inc. especially for formatting their drives. Nothing has repaired this drive. Right now, I'm transferring a 9.6Gb file and the rate is fluctuating between 1.38-3.26Mb/s.(Lenovo ThinkCenter-Win10). None of the drives in question are older than 2 y/o and one (Sandisk Cuzer Glide 3.0/256Gb) is less than 9 mos. all drives have been used, in what I'd consider, moderate to little operation. I _could _provide much more info about what I've done concerning testing the drive, but unless requested(for it's an extensive list), I'll omit that. So, here's my objective #1. Identify and correct what caused the slow-down problem #2. Restore the drives to their original "write" operating speed. These drives, according to all tests confirm these drives are not dead!!!
THANX:
*Rick*


----------



## natr0n (Feb 26, 2018)

They wear out.

Sometimes plugging into another usb slot will help speeds. If you have any usb3 ports test the stick in those.


----------



## 69Rixter (Feb 26, 2018)

Re:* natRon*

   Ah... you busted me right-off-the-bat. That is one of the "tests" I did, that wasn't in the post. Also, (maybe this is relevant) I've tested on Win 10/Win7 and LM 18.3 O.S.'s with minimal/negligent differences.


----------



## The_DriverX (Feb 26, 2018)

This might help shed some light: https://superuser.com/questions/315134/why-does-my-flash-drive-speed-slow-down-when-copying


----------



## 69Rixter (Feb 27, 2018)

RE: *The_DriverX*

*   T*hanx for the link. I've read this previously. Ahm... as i agree with the "functioning" of a flash drive, I have serious doubts that 5 drives suddenly, at almost the same time, developed the malady in question. I understand how a drive slows while writing, but in my cases(s) it's the write _speed has dropped so considerably at the start. I_'ve been trying to find what articles i can explaining 'how" a flash is written to/read from and I'm "thinking" that somewhere in my quest to understand that process, I may find an answer. Appreciate you responding and if something else should occur to you, do let me know.


----------



## newtekie1 (Feb 28, 2018)

One of the down sides of using NAND flash for storage is that once a cell has been used, it has to be erased before new data can be written to it again.  This is why SSDs have the TRIM command.  However, almost no USB flash drive, especially cheap ones, support any kind of TRIM or garbage collection.  So they they are new, write speeds will be good.  But once you have written enough data to the drive that every cell has been used, write speeds drop, because from that point on it has to erase the cell before it can write to it.

Also, this doesn't mean you have to fill the drive up before this happens.  It just means you have to write enough data to use every cell in the drive.  Flash drives do have wear leveling in them, so even if you save the same file over and over again, it will write that file to different cells.  So in the case of a 16GB flash drive, you just have to write 16GB of data to the drive for the write speed to start to degrade.  You can do this by writing about 16GB of different files to it, or just saving the same 1GB file 16 times.


----------



## jsfitz54 (Feb 28, 2018)

I would recommend you try a Low Level Format Tool.
Many flash drive makers have their own tool.

Google search:  
https://www.google.com/search?q=Kin...rome..69i57.8808j0j8&sourceid=chrome&ie=UTF-8

https://www.google.com/search?q=hdd...1.69i57j0l5.5754j0j7&sourceid=chrome&ie=UTF-8


----------



## 69Rixter (Mar 8, 2018)

newtekie1 said:


> One of the down sides of using NAND flash for storage is that once a cell has been used, it has to be erased before new data can be written to it again.  This is why SSDs have the TRIM command.  However, almost no USB flash drive, especially cheap ones, support any kind of TRIM or garbage collection.  So they they are new, write speeds will be good.  But once you have written enough data to the drive that every cell has been used, write speeds drop, because from that point on it has to erase the cell before it can write to it.
> 
> Also, this doesn't mean you have to fill the drive up before this happens.  It just means you have to write enough data to use every cell in the drive.  Flash drives do have wear leveling in them, so even if you save the same file over and over again, it will write that file to different cells.  So in the case of a 16GB flash drive, you just have to write 16GB of data to the drive for the write speed to start to degrade.  You can do this by writing about 16GB of different files to it, or just saving the same 1GB file 16 times.



RE: *newtekie1  *
Quite aware of all you've responded. As I do agree there'll be a certain 'drop-off"(speed wise) from the first few times you copy to it, that's not what happened to these drives. Everything was status quo with them until, at almost the same times, they all developed a considerable loss of write speed. The two 3.0 drives went from approx 8-9+Mb/s to 3.4-4-2Mb/s and the 2.0 drives dropped from about 5-6+Mb/s to 1.8-2.1Mb/s. I don't believe there are many (if any) pendrives employing TRIM. B-T-W, none of these drives have been used more than 2 yrs and "moderately" written to. (yes, I know ...that's subjective). To make a case-in-point; I still use a Kingston 2Gb pendrive--that's 11 y/o and no problems. (bet there's few who can say that). So, with all due respect, I think the "problem" (?)...well don't know what caused these drives to suddenly "lose writing speed". Question: what do you know about flashing the firmware of flashdrives?
TNX for responding



jsfitz54 said:


> I would recommend you try a Low Level Format Tool.
> Many flash drive makers have their own tool.
> 
> Google search:
> ...



RE: *sfitz54*

_Appreciate_ you responding. I've tried the Kingston format tool. I'm not so sure it was adequate... by that I mean when I employed it: #1 Wasn't able to access FAT32 or even FAT16 #2. Although it "said" it formatted the Kingston drive, the "progress" bar only indicated about 75%??? Any thoughts?
TNX:


----------



## Mussels (Mar 8, 2018)

You've been given the correct answer - nothing short of TRIM or a low level format will return those speeds.

Even the files you're copying can vary the speeds greatly, flash memory doesnt like lots of small files/writes, and even the size of what you're copying will have an effect (many flash drives have a smaller cache, like 128MB of high speed cache, then the remainder of the drive at the slower speed) - once you pass that buffer, it slows to a crawl


----------



## HTC (Mar 8, 2018)

Stupid question: could this be the result of meltdown / spectre fixes?


----------



## silentbogo (Mar 8, 2018)

There's only one answer: it's a fucking Kingston.
I've seen way too many problems with their drives mostly related to their choice of low-cost controllers.
For example, I had several DT100 G3 and DTSE9 G2 USB3.0 drives die due to faulty controller after only a few months of low usage. Had a pair of DTSE9 drives that suffered from the same issue as yours (read speeds as low as 5MB/s on large files, write speeds may drop to KB range), and one of them gave up completely, while the second one is in semi-alive state and cannot be used as bootable drive at all. Every time you do a manual partitioning/formatting through _diskpart_ or attempt to create a GPT partition table (which worked before), it simply fails and has to be recovered via factory diag. tool (That one uses Alcor controller, so it's AlcorMP and a following low-level format).
The other USB3.0 drive occasionally does not want to work on USB2.0 ports (even on the same machine where it previously worked). That was the last Kingston drive I ever bought.


----------



## R-T-B (Mar 8, 2018)

HTC said:


> Stupid question: could this be the result of meltdown / spectre fixes?



No.


----------



## Readlight (Mar 8, 2018)

Same happened to Sandisk Blade it writes only some Kb/s also haw drives who do not boot in bios and write protected MicroSD. Nothing better then Sandisk Extreme i haven't seen.


----------



## SamirD (Mar 10, 2018)

I've noticed this happening as a drive starts to approach it's death.  And then one day it will stop reading completely.  I never store anything important on flash drives anymore.


----------



## 69Rixter (Mar 24, 2018)

*EVERYONE:*

*Wish to thank all who've replied*. Got some very interesting/informative answers. Yes, I am aware there is a limit to all pendrive's performance, and mine are no exception. Just seems curious that 5 drives all developed the same malady at almost the same time. *TO*: *silentbogo  *I beg to differ*. *The pendrives in question were of 3 different manufactures. And, I have a 11 y/o Kingston that's still functioning as it did the day I got it. I keep getting responses referring to 'low-level" format. Isn't that what most formatting tools are? And I'd like comments on what "flashing" the drives firmware may/may not accomplish? That is/will be (if I decide to do it) the last I'll do to try to restore these drives.(BTW...Sandisk does not provide their firmware for such a task) It was never about the cost (being cheap) of a flash drive even with their recent increase in price. I wanted to know what caused the failures in 5 different drives at almost the exact same time. And, if possible, revert them back to their original working state. I tend to go with *silentbogo *when he states it has to do with the controllers in the drives.  Something has caused the deterioration of the write speeds and that very well could be the _controllers, (IDK) b_ut all 5 at almost the same time? Hmmm...???

THANX:


----------



## SamirD (Mar 26, 2018)

You bring up a good point about the controllers.  If the usb on a particular system is running voltages out-of-spec that damaged the controller or the drive, that's another possibility.


----------

