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Tech: Fast memory stick & remote XP's

18 Dec 10 - 05:33 AM (#3056238)
Subject: Tech: Fast memory stick & remote XP's
From: Mr Red

I just purchased a Corsair Flash Voyager GT

loaded it with Firefox Portable (as per old stick) and am running it from the library.

It is so fast you don't notice the stick's latency. Which was the intention. Result!

I have dial-up at home (it tests/proves my site cresby.com is acceptable for the lowest common denominator). I then use a selection of library PC's (remote instances of XP screwed down to the point of marginal use) and Radio Station PC's - XP again. So I take all my favourites/passwords/etc on the stick. Safe from prying eyes and forgetfulness on other browsers - not to mention the "Me Generation" who have a more urgent mission than me - inevitable in a dynamic shambolic scenario.

the question Why would it slow down on other machines?

The Corsair claims 30Mb/s throughput and it certainly speeds in bursts but on my XP at home it is achingly slow writing 84 Mb of MP3 by comaprison with the old stick's read speed - which may be to do with the machine (USB 2 was an afterthought by the MB manufacturers)
Or it may be that the stick draws so much power that it's management has to slow it down. They have been very clever with the design to get the speed anyway - of that I am certain - being an Electronic Engineer allows me to understand what they say.


18 Dec 10 - 06:36 AM (#3056274)
Subject: RE: Tech: Fast memory stick & remote XP's
From: Newport Boy

If you have a MB where 'USB2 was an afterthought' it's quite likely that the USB ports on the front of the machine are USB1, and the only USB2 ports are those on the back panel (and not on an expansion card).

Phil


18 Dec 10 - 06:58 AM (#3056285)
Subject: RE: Tech: Fast memory stick & remote XP's
From: The Fooles Troupe

I would really LOVE manufactures to actually give speed details on USB memory sticks, but you try and find out...

Maybe we should sub-contract Mr Assange .... :-)


18 Dec 10 - 11:08 AM (#3056419)
Subject: RE: Tech: Fast memory stick & remote XP's
From: JohnInKansas

When USB2 first appeared, some early "port expanders" warned that the USB controller could only use one speed at a time. The controller could sense what speed downstream devices were capable of, but had to select one speed compatible with them all. You could get USB2 speed only if all of the USB devices connected to it were USB2. A single USB (USB1) device connected to the system meant that all the connected devices had to run at USB speed.

"Switchable" or "Autoswitching" port expanders appeared quite soon after USB2 devices got popular, with the ability to send/receive to each device at the speed appropriate to the individual device, so you could mix USB with USB2 devices on the same controller.

Nearly all of the early "single speed" port expanders that I saw were "passive hubs" that took all their power from the USB port they were plugged into. Even the earliest "powered hub" expanders, with a "wall wart" transformer to power the hub and downstream devices independent of the port they plugged into, usually advertised the "autoswitching" capability - at least by the time I started getting any USB2 stuff.

No current devices that I've seen make any note of the "mixed version" limitation, so it's likely that all newer ports and port expanders are capable of mixing USB and USB2 devices; but if the port in the computer is of the very early kind, any USB device (not USB2) that is downstream from that controller will suck the controller down to USB speed, even if "all but one" of the connected devices are USB2.

While I can't guarantee that's what you're seeing, you might be able to check it out by disconnecting all the USB devices on the old machine that you can't confirm are USB2 certified, and see if the speed improves. You might just have one "lazy mouse" or keyboard, or printer that's dragging the whole string down, if the port in the computer, or an expander in the string you're plugging the flash into, happens to be one of the very early type.

John