How many devices can be powered by the USB ports on a computer? I am asking because when I plug my external hard drive (which has mains power as well) into my machine the lights on my keyboard dim. Also when that hard drive is plugged in and I plug in a newer expansion drive (with USB power only), the newer expansion drive won't work at all until I unplug the wifi adapter. And another thing I tried is to plug in the expansion drive and not the external and everything runs fine. Could it be a problem with just that external hard drive instead? Here is the specs of my machine: cpu: i7 965 mobo: gigabyte ga ex58 extreme power supply: gigabyte odin 1200w ram: 6gb gskill 1600ghz video card: ati 4870x2 internal hard drives: 2x western digital velociraptor 300gb. cooling: the case has 3 fans plugged into power supply not through mobo and the cpu has a water cooling system that cam with the case. case: thermaltake xaser vi. USB devices: always plugged in: basic logitec mouse razer lycosa keyboard belkin wifi adapter only use plug in these hard drive when I need to. seagate expansion drive 500gb ( that is only supplied by the usb) this works if i don't plug in the other hard drive. western digital my book 500gb (that also has addition power cable to power device). Thanks for reading if you got this far!
