Why are USB 2.0 sticks much less the 60MB/s?

[omega3]

Just got the Kingston Traveler Micro usb which is 2.0.. and yes, it's really slow.. write is 6MB/s and read 19,5MB/s

Maybe dumb question but why doesn't these sticks never write close to 60MB/s which USB 2.0 should be able to handle.. i don't get it

I got the Kingston micro because of its very small size to leave in so you won't accidentally bump against it and gonna use syncback for backing up certain files.. not sure anymore if that's a good idea :'(

 

[LTC8K6]

"Due to bus access constraints, the effective throughput of the High Speed signaling rate is limited to 35 MB/s or 280 Mbit/s."

The other limitation is the flash memory used in the card or stick, I think.

 

[MongGrel]

NM.

 

[omega3]

"Due to bus access constraints, the effective throughput of the High Speed signaling rate is limited to 35 MB/s or 280 Mbit/s."

The other limitation is the flash memory used in the card or stick, I think.

So if USB 2.0 is to limited 35 MB/s how come usb sticks never give that.. mine is even only 5-6MB/s write

 

[LTC8K6]

Have you tried them in a USB 3.0 port?

That would tell you what the stick is capable of, if it higher than the 2.0 port is showing.

IIRC, my 2.0 sticks are faster in a 3.0 port.

 

[omega3]

Have you tried them in a USB 3.0 port?

That would tell you what the stick is capable of, if it higher than the 2.0 port is showing.

IIRC, my 2.0 sticks are faster in a 3.0 port.

If the stick can only write 5-6 MB/s, why would a 3.0 port make any difference if it doesn't even come close to 2.0 limits?

 

[LTC8K6]

Just ran HDTach with an old 8gb Sandisk Cruzer plugged into my old laptop. 2.0 port and 2.0 stick.

Got 23.6MB/sec. average 29 burst.

 

[LTC8K6]

If the stick can only write 5-6 MB/s, why would a 3.0 port make any difference if it doesn't even come close to 2.0 limits?

The problem might be the port...if so, the transfer rate will be higher in the different port.

 

[LTC8K6]

Same stick in a really old pentium laptop.

15 average 20 burst.

 

[Red Squirrel]

My guess is it's more a limitation of the flash. They probably don't use as high end NAND chips as they use in SSDs.

I just tried using dd with bs=100M and a random USB stick I have here and got 6MB/sec write and 19MB/sec read. So yeah kinda terrible. But to be fair I rather them use lower end flash and make them really cheap as I see them more like floppies, just used to transport data around. If I want fast speed I'll use a SSD.

As a comparison on one of my raid 10 arrays with same command I get ~330MB/sec write and ~230MB/sec read. (that's kinda odd actually, I figured read would be faster). This is probably not the best test though, I just picked 100M chunk size arbitrarily. There's probably a science to what should be a good size to test with.

 

[Insert_Nickname]

My guess is it's more a limitation of the flash. They probably don't use as high end NAND chips as they use in SSDs.

Quite right. NAND used in USB drives tend to be lower quality then that used in SSDs.

There is also protocol, bus and file system overhead. Try and format the stick with exFAT with a higher allocation size (64-256KB). Experiment a bit to find the optimal size for your particular drive.

"Due to bus access constraints, the effective throughput of the High Speed signaling rate is limited to 35 MB/s or 280 Mbit/s."

I can get 35.4MB/s out of my USB2 ports. Must be some sort of record...

 

[omega3]

Quite right. NAND used in USB drives tend to be lower quality then that used in SSDs.

There is also protocol, bus and file system overhead. Try and format the stick with exFAT with a higher allocation size (64-256KB). Experiment a bit to find the optimal size for your particular drive.

I can get 35.4MB/s out of my USB2 ports. Must be some sort of record...

So how should i format the usb stick best.. when i right-click to format i can choose exFat if that's really better and then clustersize or something that let's me choose either 32kb, 64kb, 128kb, etc.. you get the idea.. so a fixed value but not a range..

is it however smart to use exFat.. im only gonna use the stick with this computer but i heard it is still best to use fat 32 and also not nfts.

I'm not a formatting expert so all advice welcome.

btw.. i have the Kingston Traveler Micro USB stick from amazon.. i mainly got that very small stick cause you can leave it in cause it doesn't protrude.. most reviewers say they got similar speeds like me so not sure if changing formatting will do much about that but if it could actually help then what should i try?

 

[LTC8K6]

http://www.anandtech.com/show/4523/usb-30-flash-drive-roundup/7

 

[Insert_Nickname]

So how should i format the usb stick best.. when i right-click to format i can choose exFat if that's really better and then clustersize or something that let's me choose either 32kb, 64kb, 128kb, etc.. you get the idea.. so a fixed value but not a range..

That's because there is no one cluster size to fit all. HDDs f.x. used to use 512B sectors. Today they use 4KB sectors. Enterprise use a whole range of different sizes. A large cluster size also result in more wasted space, since data is allocated, again f.x., two clusters even if there is only a single KB more then can be fitted into one cluster.

NAND flash memory has the added disadvantage that data can only be deleted by the internal block. Such a block can range from 64KB and upwards. So to fit two f.x. two 8KB files/writes would take one whole block of f.x. 64KB. If the file system already knows the block size is 64KB everything is fine, since it'll just combine those two into a single write. But if it doesn't those two 8KB writes could end-up in two different blocks, which cannot then be used for anything else. Hence you've used 128KB for two 8KB files. It also means the controller has to access two different blocks to read those files. Which is also slower, of course.

Hope that makes sense, it is a complicated subject and no really amenable to short explanations...

is it however smart to use exFat.. im only gonna use the stick with this computer but i heard it is still best to use fat 32 and also not nfts.

I'm not a formatting expert so all advice welcome.

You could think of exFAT as a sort of "FAT64". It's not really supported outside of the PC/MAC ecosystem. But everything back to XP can read it. XP does require a patch and Vista SP1 however.

In short its not really a universal exchange format. But works fine for 7 and newer.

BTW, don't use NTFS on USB sticks. There are a whole multitude of reasons why that's a bad idea.

btw.. i have the Kingston Traveler Micro USB stick from amazon.. i mainly got that very small stick cause you can leave it in cause it doesn't protrude.. most reviewers say they got similar speeds like me so not sure if changing formatting will do much about that but if it could actually help then what should i try?

Slow'ish read/write speed on USB sticks/SD cards/etc. are quite common. You'll need something like Corsairs Flash Voyager series drive to get a "high-performance" USB stick.

 

[Mantrid-Drone]

BTW, don't use NTFS on USB sticks. There are a whole multitude of reasons why that's a bad idea.

Interested: please explain this more.

 

[Valantar]

There is no such thing as a very compact, high performance flash drive. Small flash is (usually) very slow. USB flash controllers are slow. Both are designed and developed for size, price and ease of manufacture. Speed just isn't a concern in this segment. Even most "fast" (not "ultra") USB 3.0 drives top out around 100MB/s - and they're still quite large.

 

[Insert_Nickname]

Interested: please explain this more.

NTFS uses file journalling. Equals more unnecessary writes. What's more accidentally removing an NTFS disk while there is disk activity can cause weird errors, both on the PC and drive. NTFS does a lot of work in the background, so it's often you're not even aware there is activity. Then there is the whole compatibility with OSX issue. I also doubt you'll ever need file permissions or disk quotas on a USB stick...

 

[Mantrid-Drone]

Thanks for the info.

Would that same "work in the background......." apply to NTFS formatted external USB HDDs.

I ask because I have often noticed that when trying to disconnect such a HDD, in the correct way of course, it tells me it is being used by some other program. This despite the fact there is no indication of HDD activity on the computer or the external HDD itself.

 

[Joepublic2]

Quite right. NAND used in USB drives tend to be lower quality then that used in SSDs.

There is also protocol, bus and file system overhead. Try and format the stick with exFAT with a higher allocation size (64-256KB). Experiment a bit to find the optimal size for your particular drive.



I can get 35.4MB/s out of my USB2 ports. Must be some sort of record...

I just hit 39.4MB/s with my 2.5 inch external drive (using UAS, BOT is slower I'm sure)

 

[Cerb]

is it however smart to use exFat.. im only gonna use the stick with this computer but i heard it is still best to use fat 32 and also not nfts.

Windows will use large FAT32 partitions just fine, and will let you format them up to 32GB.

exFAT can be totally hosed by corruption of the file allocation table (FAT), whereas FAT32 has an alternating FAT, so as long as the last write was synced up, the current write screwing up can be rolled back (it may result in corruption of the file(s) being written, but exFAT can just go TU in such situations). exFAT also uses blocks that are way too big for anything but high-res photos and videos, by default. We only have it because of management in multiple major companies acting like bratty kindergartners (playing chicken over who is willing to give up IP, who is willing to pay royalties, who is willing to implement something they didn't invent, etc.), and it is not a good fit for general-purpose use. I am not a fan, as you might guess. If you look at how it works, as it as extended from FAT32, the whole, "it's optimized for flash devices," BS becomes overwhelmingly clear as BS. Its few good features, like transactional integrity (which is how MS allowed mitigation of the FAT corruption risk, for Windows CE devices), are optional, and so not implemented anywhere you'll use a flash drive.

But, FAT32 can't do >4GB files, many devices don't support NTFS, and some flash drives such bad random write performance that NTFS can be downright painful (with OK random write performance, even around 4KB@0.2MBps, NTFS is about as fast as FAT32). So, pick your poison, and try to always remember to unmount before removing.

 

[Cerb]

NTFS uses file journalling. Equals more unnecessary writes. What's more accidentally removing an NTFS disk while there is disk activity can cause weird errors, both on the PC and drive. NTFS does a lot of work in the background, so it's often you're not even aware there is activity. Then there is the whole compatibility with OSX issue. I also doubt you'll ever need file permissions or disk quotas on a USB stick...

Been using NTFS on USB drives for ages, in large part because it really is better in practice than the two other common file systems, IME, occasionally just pulling them out (if safely remove hardware fails, FI), and nothing generally goes wrong, as opposed to when doing that with the FATs. As long as there is plenty of free space (so tht it can write new data in free space, instead of truly overwriting, in the case of editing a file), it can roll the FS back, just like you internal drive after a power failure. Compatibility is more of an issue, but only for OS X and set-top boxes.

 

[Cerb]

I can get 35.4MB/s out of my USB2 ports. Must be some sort of record...

40.2, cloning with Clonezilla, to a 7-series Intel USB 2.0 port, from a Thermaltake USB 3.0 dock. It was a SATA SSD, of course.

 

[jji7skyline]

My USB3.0 flash drive only gets around 6MB/s write and 7MB/s read.

 

[Insert_Nickname]

Been using NTFS on USB drives for ages, in large part because it really is better in practice than the two other common file systems, IME, occasionally just pulling them out (if safely remove hardware fails, FI), and nothing generally goes wrong, as opposed to when doing that with the FATs. As long as there is plenty of free space (so tht it can write new data in free space, instead of truly overwriting, in the case of editing a file), it can roll the FS back, just like you internal drive after a power failure. Compatibility is more of an issue, but only for OS X and set-top boxes.

I'm not saying you shouldn't use NTFS for external HDDs. That is perfectly legitimate. I was specifically targeting flash drives.

40.2, cloning with Clonezilla, to a 7-series Intel USB 2.0 port, from a Thermaltake USB 3.0 dock. It was a SATA SSD, of course.

Oh, if we're allowed USB3 stuff, I can get ~42MB/s with the ASUS BOT driver on the Intel 7-series xHCI controller. The 35.4MB/s above was for the standard Intel EHCI controller, and an equally unremarkable external HDD...

 

[Cerb]

I'm not saying you shouldn't use NTFS for external HDDs. That is perfectly legitimate. I was specifically targeting flash drives.

Me too. Had one get hosed around maybe '05 or '06, went to NTFS, and it's mostly been good since. There should be no difference between an HDD and thumb drive, so long as the controller doesn't go haywire if unplugged while writing.

Oh, if we're allowed USB3 stuff, I can get ~42MB/s with the ASUS BOT driver on the Intel 7-series xHCI controller. The 35.4MB/s above was for the standard Intel EHCI controller, and an equally unremarkable external HDD...

USB 2.0 on the PC side, with whatever drivers were in the kernel. I had meant to use USB 3.0, but Dell makes all the ports black, so I ended up using the wrong one.