What is the correct speed for USB2?

the_syco

Hi all,
Recently got a 16GB Sandisk Flash Drive from Tescos for €14.98 with the model of it being "SDCZ37-016G". My problem is that it only copies stuff at 5.4 MB/sec as opposed to a speed of 29 MB/sec that I get with a WD Passport drive. I'm wondering is the SanDisk flash drive defective, or is this normal?

PogMoThoin

Thats normal for a usb key, the fastest You'll get on a usb key is 15MB/sec write and about 30MB/sec read for a super-duper expensive one, this is a cheapo-nasty Tesco one
If You want speed avoid usb.

cherryghost

USB 3.0 ftw

Venom

cherryghost wrote: »

USB 3.0 ftw

Yeah in a year when tech supporting it comes out

the_syco

Venom wrote: »

Yeah in a year when tech supporting it comes out

It has been on mobos for the past few months. Not sure what size flash drives are USB3, though, nor their price.

Venom

the_syco wrote: »

It has been on mobos for the past few months. Not sure what size flash drives are USB3, though, nor their price.

Motherboards and USB 3.0 addon cards are all I can find at the moment and until USB HD enclosures and flashdrives come out it just wont take off.

Bob_Harris

cherryghost wrote: »

USB 3.0 ftw

You can have the link between the computer and disk as fast you want but if the disk cannot keep up, what's the point?

TouchingVirus

Bob_Harris wrote: »

You can have the link between the computer and disk as fast you want but if the disk cannot keep up, what's the point?

Exactly.

Theoretically USB 2.0 has a max transfer speed of 480mbits/sec (60 MB/sec). Taking into account transfer overhead it's more like ~40MB/sec. This is the max speed the bus supports, but that doesn't mean you're destined to get it. Lots of other factors come into play, the speed of the drive being written to is the most important. The reason I never bought a Tesco 16GB drive was that I figured it's read & write speed was p*ss poor and by the sounds of it I was right.

In future pay more attention to the read & write speeds for flash drives and you'll be fine. External hard drives aren't so hard to get wrong, they all spin fast enough for 40MB/sec

cherryghost

uhu uhu but I have an SSD, so yeah.

16GB USB3 sticks are starting at 50 quid by the way

ressem

Having a USB 2 interface or USB 3 does not guarantee that a device will transfer data at anywhere close to the theoretical limit of the interface. Manufacturers can put a usb3 interface on a portable floppy drive, but it might even get slower.

The speed of this device is not limited by the USB 2 interface, it's limited by the internals of the key; the choice of flash memory chips, how they are configured and controllers.

There's a pile of Sandisk types, many are faster, but some are around the speed you measured...
http://usbspeed.nirsoft.net/
for an idea of how the speed can vary between models.

Bob_Harris

cherryghost wrote: »

uhu uhu but I have an SSD, so yeah.

16GB USB3 sticks are starting at 50 quid by the way

http://crystalmark.info/software/CrystalDiskMark/index-e.html

Go on, impress us with the real world Read / Write speed of your SSD.

Have a link to the USB3 Flash disk?

Menengroth™

Bob_Harris wrote: »

http://crystalmark.info/software/CrystalDiskMark/index-e.html

Go on, impress us with the real world Read / Write speed of your SSD.

Have a link to the USB3 Flash disk?

Can everyone play?



:pac:

wolfric

maybe one of the mobs could add that nirsoft link to a stickey up the top? (http://usbspeed.nirsoft.net/)

simoniz

3.0