I have Dell LCD monitor with a built-in USB hub, that is connected to a Dell OptiPlex GX270 computer. The monitor has a USB cable that plugs into one of the ports on the tower. But about half of the time, if I turn the monitor off, and then on again, Windows XP sees it as a new USB device and opens a window saying “This USB device can perform faster if you connect it to a high-speed USB 2.0 port.” WTF? All of the ports on this computer are USB 2.0! Any clue whats going on?
Is any USB device connected to the monitor hub? Are the monitor ports 2.0?
Nope, nothing plugged into the monitor. According to Dells specs the hub is USB 2.0 compliant.
What cables are you using? Are you using the one that came with the monitor?
If you’re using a different (read: cheap) cable, it can force the connection to go down to USB 1.1
You may ask “but why would that make any difference? The cables are the exact same!”. And I’d reply, “You’re right! They are the same! But there’s just one problem”
See, when USB 1.1 was the standard, some of the really cheap (generally overseas) cable companies realized they could get away with cheaper cables to use as USB. This was fine for the lower speed USB ports, but when 2.0 came around, it used the cable much more efficiently… And suddenly the cheap cables couldn’t handle the full speed. Why? The cheaper cable they used was a different, cheaper alloy or not shielded as well… The list goes on and on.
I have a USB extender that does this (I have a joypad attached to it, so it’s not like speed matters) Anything that plugs into it goes down to low speed… Luckily I have a USB 1.1 Hub too, so all my non-speed critical devices (keyboard, mouse, joystick… I think I even have a printer in it) all plug in there nicely.
I also don’t want this to come off as an advertisement for those expensive cables you see at big box stores - a USB cable should NOT cost $40 for a 6 foot length. By all means, find the cheapest cables you can ($10 should get you pretty much anything you need, unless you want to go much further) but make sure they do what you want them to do.
A couple of other possibilities which may or may not apply to your situation.
Windows XP prior to SP1 did not support USB 2.0. If your computer was originally installed with an old version of XP and then upgraded, you may need to go to Control Panel and Remove/Reinstall your USB ports.
Also, some models of motherboard have a utility on the CD that came with them that needs to be run (after installing XP SP1) to activate the high speed functionality of the USB ports.