I am trying to understand why usb is so unreliable? I constantly have problems when trying connect more than say 2 devices to my motherboard. I am not going to give you the list of items that are unreliable but they are random and sometimes they work and sometimes they dont! (My system runs all the lastest greatest drivers and updates & I format my hard drive once a year for preventive maintenance!) I do remember while studying for A+, that you can connect 127 usb devices but the limitation is the power. Unfortunately manufacturers dont feel the need to explain, address, or identify high power consumption devices.
My thought is that any device that also plugs into the wall will not knock out your hub. I was wondering though if there are people that use external hubs and still experience this?
I recently looked at a "read me" about plugging a hub into a hub being a BAD IDEA! However any USB hub you plug into a USB port on you computer is doing that right? If you plug an externally powered 4 port hub into a serial port is that a work around?
All of my USB ROOT HUB entries in device manager say [THE HUB IS SELF POWERED TOTAL POWER AVAILABLE: 500mA per port.]
I cannot change this value, and it doesnt seem that a new power supply is going make 500mA more avialable! Is it the motherboard that is failing to suply the current for these devices? Maybe $300.00 motherboards dont have this problem? Do they?
The other X factor is from USB UNIVERSAL HOST CONTROLLER under advanced tab it states; The table below shows you how much bandwidth each USB controller is using. Each USB controller has a fixed amount of bandwidth, which all attached devices must share. All of my 5 USB UHC's say that they are using 10% of the system bandwidth.
If the ports/hubs were numbered and identified I could make sure I only plugged 1 device into each hub!
Sorry to rant but I am at my witts end. Does firewire act like this?
My experience of USB 2.0 is also crap.
First, WIN XP have crap support for it, you need SP3 and it is still crap.
Main solution when it was working and then goes bad is to remove all USB drivers and allow them to auto detect hardware and reinstall. Then things work ok .....for a while.
I have found the USB plugs on my laptop are different or the cable plug is different, ie in how good a connection they make.
Wiggle the plug and it will work or will stop working, contacts are poor, sometimes you get good contact only by pulling the plug out slightly. Best indication is if the USB device you are plugging in has a LED light that will glow when you have a connection.
When you have poor contact, the USB device is just not detected by the PC. ie nothing happens.
Apparently on connection of the USB device, a test signal exchange determines if it is high speed or not. This test is very unreliable and the default then is slow speed. Hence the poor performance you experience when it was working at say 18MBytes per second and now only 1.5.
Hope USB 3 resolves the problems?
PS a great utility that even indicates the USB device current drain is called ListUsbDrives.exe from German guy - see:
USBDLM V4 - USB Drive Letter Manager for Windows 2000, XP, Server 2003 and Vista