EdwinJ85
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Max USB stick transfer speed for the pi?

Tue Feb 05, 2013 11:07 am

Hi everyone,

I was wondering if anybody knew what the max USB transfer (read/write) speed for the raspberry pi is please? I'm hoping to boot Raspbmc of a USB stick rather than an SD card to improve performance.

I know the max SD card size and speed is 32GB and around 20 MB/s, is this the same for USB sticks?

Thanks,

Edwin.
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remsnet
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Re: Max USB stick transfer speed for the pi?

Tue Feb 05, 2013 11:43 am

EdwinJ85 wrote:Hi everyone,

I was wondering if anybody knew what the max USB transfer (read/write) speed for the raspberry pi is please? I'm hoping to boot Raspbmc of a USB stick rather than an SD card to improve performance.

I know the max SD card size and speed is 32GB and around 20 MB/s, is this the same for USB sticks?

Thanks,

Edwin.

An PI has only USBv2 .
Thus the maximum speed of the SD card witch been connected over that limted by USBv2.

regards.

ski522
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Re: Max USB stick transfer speed for the pi?

Tue Feb 05, 2013 11:44 am

The Pi supports USB 2.0 specification which allows for transfer speeds up to 480Mbit/s or 60Mbyte/s. USB flash drives can reached up 33MBytes/s, but there seems to be some limitations in the NAND itself so it will come down to the type of stick you get. Also while these are bus speeds, I'm not sure the Pi is able to hit those full rates just because of the CPU speed in general. Also SD cards are more then capable of hitting that same read speed, so I see little benefit in booting from an USB flash stick.

EdwinJ85
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Re: Max USB stick transfer speed for the pi?

Tue Feb 05, 2013 2:33 pm

ski522 wrote:The Pi supports USB 2.0 specification which allows for transfer speeds up to 480Mbit/s or 60Mbyte/s. USB flash drives can reached up 33MBytes/s, but there seems to be some limitations in the NAND itself so it will come down to the type of stick you get. Also while these are bus speeds, I'm not sure the Pi is able to hit those full rates just because of the CPU speed in general. Also SD cards are more then capable of hitting that same read speed, so I see little benefit in booting from an USB flash stick.
Hmmm, yeah I see little difference between a 30MB/s speed and a 20MB/s + sd card read speed of the PI, other than USB 2.0 sticks are a lot cheaper than SD cards that are faster than class 10 - 10mb/s cards. Considering the fact you have to boot from an SD card anyway, I'll keep to the SD card for now, I may buy a faster SD card than my current 32GB samsung class ten though.

I know random access speed is also important, but that sort of measurement is beyond my brainpower. :(

Thank you. :)
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RaTTuS
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Re: Max USB stick transfer speed for the pi?

Tue Feb 05, 2013 2:47 pm

having the rootfs on an external HD will improve performance because of random access times are better
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EdwinJ85
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Re: Max USB stick transfer speed for the pi?

Tue Feb 05, 2013 5:18 pm

Ah, so 4k and 512k block read/write times are faster on a USB stick? Do we know how much faster?

Sequential read is all I need to worry about for playing movies etc right? ext4 stores things pretty close together but leaves them room to grow so it's less fragmented than NTFS if I remember right.
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Re: Max USB stick transfer speed for the pi?

Wed Feb 06, 2013 9:05 am

I've been trying to optimise i/o speed on my pi and am trying to find a faster thumb drive but am not very sure how to determine how it will perform before purchasing a new one.

My class 4 sandisk sd card gives 20 MB/s; cheap thumb drive gives 15 MB/s and a powered Seagate HDD gives 25 MB/s. These are sequential write speeds and I still seem to get better overall performance running with the rootfs on the slow thumb drive, presumably due to random access speed.

What I'd like to do is find a thumb drive that gives performance comparable to the external HDD but am not sure which to go for because they all seem just to quote USB 2.0 as their speed but I'm sure not all are created equal.

Anyone know of any benchmarking test results for various brands of thumb drive?

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Re: Max USB stick transfer speed for the pi?

Wed Feb 06, 2013 9:12 am

if all you are doing is playing back movies then USB sticks are the way to go as random access speed is not that important.
if you are using it as a computer then moving the rootfs to a real HD on the usb [not a stick] your experience will be much better.

if I can I'll do a couple of tests today highlighting boot speed for example ....

quick edit
I cannot do a good test as my HD image has much more installed on it and starts several extra services - if I go though the process again on another one I can do a test then [the SD parttition 2 has a backup boot option sort of thing now ]
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EdwinJ85
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Re: Max USB stick transfer speed for the pi?

Wed Feb 06, 2013 9:38 am

Thanks, benchmarks would be awesome. I'm using Raspbmc atm and watching movies mostly off the device but I do have transmission set up and I do stream from the pi to other machines in the house. I'm not sure if random access is important or not in this setup.

I tested the card with sd parm and a few other tests last night, I'm getting around 20MB/s reads and 10MB/s writes sequentially on my 32GB class 10 samsung sd card. I know writes aren't that important either way but I'm quite impressed with the read speed.

I don't fancy compiling the other test programs on my media server (it's in constant use) and I can't take the card out atm, so I can't get any better figures unless there is a tool I can install with sudo apt-get install?
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ski522
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Re: Max USB stick transfer speed for the pi?

Wed Feb 06, 2013 12:29 pm

EdwinJ85 wrote: I may buy a faster SD card than my current 32GB samsung class ten though.
Class ratings on SD cards are write speeds only...most SD cards (regardless of class rating) read at the same speed...Just a FYI as it's common for a lot of people to think class speed is both write and read speeds.

EdwinJ85
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Re: Max USB stick transfer speed for the pi?

Wed Feb 06, 2013 1:58 pm

Ah, really? I thought the class was the MINIMUM of the read and write speed sequentially, and that while it can be a lot more it can never be less. Wikipedia says as much:

https://en.wikipedia.org/wiki/Secure_Di ... ass_Rating

The SD Association defines standard speed classes indicating minimum performance to record video. Both read and write speeds must exceed the specified value.

Hmmmm. Should have spent less on a lower class card then! Still, the 32GB comes in very handy on a media center, 1080p video can take up too much bandwidth to stream well.
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Re: Max USB stick transfer speed for the pi?

Tue Feb 24, 2015 1:30 pm

I go on here with my tests.
I do this for ideology and pleasure, I don't care about saving 30-50€: I wanted a NAS made by a raspberry because I like this little game.

Raspberry B, Verbatim SD card class 10 with pre installed noobs (http://www.ebay.co.uk/itm/8GB-MicroSD-C ... OC:IT:3160)
Raspbian, SAMBA, cable connected to my LAN (by a hub 10-100, not gigabit).
Two generic External Cases USB3 with usb3 cable, formatted ext3. On my pc (debian) the transfer speed is between 33 and 90 MB/s (Mega Byte) depending from the configuration (usb port 2 or 3, with cables usb 2 or 3 ..... no relevant to here).

With these external HD connected to the Rasp, coping big file (movies) I measure (rsync -avh --progress):
- from an external USB to the other 2,34 MB/sec (average)
- coping from my pc to an external Hd connected to the Rasp 3,5 MB/s
- interesting that from rasp to my pc there is a very little but constant difference (less than 5%).
I can't see appreciable differences using the terminal or the nautilus of Debian.

From an external HD to the SD card (/): first time 2,34MB/s, repeated twice, 3,72MB/s and 5,37MB/s (same file, same way,same situation)
from SD to external 5,16 (the same file in the same way) 5,16 first and 5,23 second time.
I see differences but I can't imagine any answer.
Did anyone else made similar test?

Architect
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Re: Max USB stick transfer speed for the pi?

Thu Feb 26, 2015 4:05 pm

Did anyone tested her or his Raspone?
Please, do share your results! I can't believe on mines, they're too bad.

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Re: Max USB stick transfer speed for the pi?

Wed Mar 04, 2015 8:37 am

Via FTP using rspc instead of raspbian: 10,9MB/s.
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