YOu can plug them into the motherboard but that would take up your mobos power. And they run at speeds according to how fast your comps running like on load. Like i had one led fan plugged in when comp was just sitting there the leds would flash because they had only got enough power to spin at about 650 rpm. And when it was like 50% cpu usage they had gone up to about 5000rpm and almost spun out. So leave them plugged into the powersupply. WOrks BETteeR!
P4 2.26 ghz, Intel d850emv2 mobo, 768mb of pc800, sony 4x dvd-rw, teac burner, nvidia ti4600 graphics, enermax 330watt ps
4 silent uv fans, cold cathodes in full tower antec case, round ide cables
SOny vaio 2.66 ht ghz modded into raidmax case with green cold cathodes.
P4 2.8ghz HT, 512mb ddr, Intel KD865gbfl, onboard video, raidmax case, blue cathodes, round ide, loomed wires, 4x dvd burner, wd sata 80gb hard drive
Intel d865perl, 2.8ghz northwood, antec sonata, wd caviar 20gb, Corsair 512mbx1 for now. 380watt psu, ati 9600, dvdrom cdrw floppy in black too match case