Extreme fluctuation of "write" speed

[69Rixter]

I have a Sandisk 3.0 256gb pendrive that has been getting weird on me. When writing to the drive, it will start out at approx. 28-32 mb/s, then almost immediately drop to 20-22 mb/s and will stay at that rate for a bit. Then suddenly it will drop to 5, then 4, etc. down to 350 kb/s(sometimes even 0)...sit there for a few secs(upwards of 30 secs)., then bounce back to 20-22 mb/s. It will do this throughout the writing process. I usually have files in the neighborhood of 8-15 Gb's. I have been in touch with Sandisk. They expressed I use 'CrystalDiskMark "., but I couldn't get it to "read" the drive (because of it's size...I think(?). I want to know what's going on with the pendrive before I have a consultation with Sandisk. Could this issue be a "controller" going bad? Oh, and ever stranger, it does not seem to be nearly as much of a problem when using Linux. ?????
[SanDisk Cruzer Glide 3.0 256Gb/format NTFS--Win 10.]

Rick

 

[IntelUser2000]

USB Pendrives suck. They not only use the worst quality NAND but a crappy controller. I have many that just died on me. I have a Cruzer 1GB device that's rated at 120MB now. That's the better one. The rest just refuses to read.

It's probably running out of its tiny buffer when you are transferring large files. You get what you paid for. This is why SSDs are much more expensive per GB then the pen drives.

 

[bononos]

You can do a bit of rough calculation about when the typical pendrive thats using tlc nand will completely fail.
Someone has done some real world testing and found that tlc pendrives failed as expected around 500-1000 p/e cycles.
https://goughlui.com/2017/05/30/experiment-8gb-usb-flash-drive-endurance-test/
Googling also gave some older studies which used MLC which had far higher endurance.

I don't know if there are pendrives advertised as using MLC. The only MLC sdcard I know for certain is Samsung pro model. The Transcend high endurance sdcards are more expensive than other high endurance cards (which may use 3d tlc) so its probably MLC.

Did more checking and theres industrial grade SLC usb thumb drives available by Digikey, Swissbit but they are expensive. Digikey's 1Gb usb drive is $24.