USB 2.0 Speed Check (?)

Hoping someone can find/has a better answer than I do...

 

My computer's USB 2.0 equipped. I feel like the transfer times I'm getting off

of my lexar card reader and Lexar Pro 133x 2.0GB are slower than they should

be.... Can anyone point me to some sort of test/diagnostic to run to see if, in

fact, my transfers are at normal USB 1.0 or 1.1 speeds? I'm hitting the 4-5

minute mark for 75%+ full cards (1.5+ GB).... Or, do I just need to be more

patient?

 

Any help/advice is most welcomed!

 

-Mike

You may need a faster card reader. The limit is normally the reader, not the USB 2.0 connection. You can theoeretically get 60MBytes/s down a usb 2.0 cable, but when you add in the timing signals and other overheads, the best you can possibly do is maybe 40 MBytes/s if there isn't something else limiting transfer speed.

 

USB 1.0 maxes out at 1.5MBits/sc and 1.1 at 12MBits/sec. Divide those number by 8 to get MBytes/s. You aren't running USB1.x. It would takes hours to download 1.5GB at USB 1.0 speeds.

 

133x cards should do about 20 MBytes/sec in theory, on a fully optimized system with fully optimized hardware and software.

 

Most card readers are much slower (I don't know why). I think Sandisk make a super-fast reader for their Extreme IV series. You can even get it in a firewire version for a little extra speed.

 

What I do is start the download and go and make coffee (or lunch if it's a big card). When I come back, the download is finished!

Thanks for the tips, Bob --- the Coffee Protocols are in full effect here at the studio. Guess I hadn't known, too, that readers have an effect on speed; thought their impact on transfer was minimal/passive, i.e., not part of the speed equation.

 

Thanks for all you do 'round here - I've found your posts to be informative, well-balanced, kind, and gracious. Much appreciated!

 

-Mike

I have tested about a dozen different CF and SD card readers with my stock of cards,

mostly Sandisk Ultra II/Extreme III SD-CF, and Transcend 150x SD now. Many seem to top

out at around 2.5 to 4.5 Mbytes@second maximum transfer speed (read).

 

I've been unimpressed with the Lexar card readers and returned both of the ones I bought

and tested. The fastest I've found to date are the Sandisk ImageMate 12-in-1 USB 2.0 and

the Sandisk Extreme III CF + SD reader. With the Extreme III SD cards, it will transfer a full

2G card in about three minutes time, just shy of 11Mbytes@second.

 

Not enough time for coffee, however. ;-)

 

Godfrey

I second the Sandisk ImageMate 12-in-1 USB 2.0, great speed but a little on the expensive side if bought local.

Sandisk claim their Extreme 3-in-1 card reader will do 20MB/s via USB 2.0. The Extreme firewire (800/400) will do 40MB/s (but it only takes CF cards)

Sandisk claim their Extreme 3-in-1 card reader will do 20MB/s via USB 2.0. The Extreme firewire (800/400) will do 40MB/s (but it only takes CF cards).

 

My various and assorted generic card readers and the readers built into printers and portable hard drive seem to be mostly in the 1 to 3 MB/s region, though all are USB 2.0.

 

The Sandisk 3-in-1 extreme is only $25 or so. Maybe I should get one and give up the coffee!

I know what they claim, Bob, but timing it and watching the IO monitor on a real computer

shows what it actually does. :-)

 

G

The efficiency of the computer could have alot of effect on it too, given's USB's processor usage.