USB Speed

[Rossua]

Can anybody please advise me as to the data transfer speeds which can be expected in practice with a USB 2.0 port.

I have a digital camera which I have tried on an older machine with USB 1.1, and for interest I compared the data transfer rate obtained with that obtained when connected to a newer XP machine with USB 2.0.

With the USB 1.1 connection I got a transfer rate of 0.61MByte/sec, and with USB 2.0 it was 0.77MByte/sec.

I would have expected a much larger difference as USB 2.0 is supposed to be 40 times faster than USB 1.1.

Does anybody know why there is so little difference in these speeds, or is my new PC with USB 2.0 possibly not set up properly, and transferring data via USB 2.0 too slowly.

thanks in advance for any advice

Ross

[Panama Red]

Check your USB devices in Device Manager and make sure you see one marked "Enhanced". That will indicate that 2.0 is enabled. If you're dowloading directly from the camera and not from the digital media in a reader of some kind, it may be the camera that is limiting the speed.

[Rossua]

There is an entry in Device Manager that says "Intel PCI to USB Enhanced Host Controller" and also one which says "USB 2.0 Root Hub", so it looks like USB 2.0 is enabled.

I tried taking the SD memory card (Viking Interworks 512MB) out of the camera and transfering the data to a laptop using a MMC/SD/MS card reader, and the data transfer rate there was 0.9MB/sec, which would suggest the memory card is the main speed bottleneck when on USB 2.0 (assuming this is a typical transfer speed for these type of cards), with the camera itself adding a little more bottleneck in addition that.

Regards,
Ross

[glc]

Is that card reader USB 2.0?

[Jaggannath]

I have the same thing on this computer Rossua, but a dialogue box pops up each time telling me a high-speed device is plugged into a non-supporting hub, and to click on it to fix it. Of course, this being an older computer (it only has 2 USB ports it's that old ), there isn't really an easy fix that doesn't involve money and effort

[Rossua]

The card reader is built in to the laptop and has 2 slots, one for SM card and one for SD/MS/MMC cards, but I don't know if it uses USB in any way internally. Here is a photo of it :-

[IMG]cardreader.jpg[/IMG]

[Rossua]

That device must need the high speed USB 2.0. The camera I attached though works just as well under USB 1.1, with only about 20% slower transfers, even though it says in the manual it uses USB 2.0.

You can get PCI cards containing 2 or 4 USB 2.0 ports, some around £5-10GBP on EBay, and they usually need PCI version 2.1 or higher, (which all but the very oldest PC's have).

PS can anyone tell me how to insert an image in a post, as in my last post it only comes up with the text of the [IMG] tags enclosing the file name.

Regards
Ross

[glc]

Please use attachments instead of inline images. We are trying to keep these forums dialup and low screen resolution friendly. Small images are acceptable, but you must load them to a website that allows external linking, and you have to put the full URL in the image tags.

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