Ok, so please folks could you advise me which way would be better. I've given a job to build a LED light.the light is a cube shaped lamp which i built myself and put all the diodes in , and now I have to think which way of wiring them would be the best.basically I have 98 red colored 3w led's. around the corners for effect there are some 12 blue ones and 6 orange.all of them are 3w rated power , now I checked the datasheets and they say that the red ones have 700mA of current and 2.0 to 2.5 of voltage drop across. the blue and orange ones have the same 700mA but a bit higher about 3.3 to 3.5 volts across them. the dilemma here for me is how to wire them given that i have only few choices, first one is to use a pc power supply and somehow arrange the leds parallel in chunks and use the 3.3 and 5 and 12v lines from the psu or just wire them all in series and use a higher voltage DC source , the latter case would be easier. I could take the mains 230v and rectify then filter with some caps and I would get 325v DC adding some leds to the count would make them enough to be able to put 325v across them.in this case I would use a 1:1 isolation transformer before the bridge rectifier. I'm bothered with this because the pc psu way would be better to my mind but due to the difference in the LED forward voltages and the voltages I can get out of the pc psu I would have to use some current resistors in series and they would waste quite some power and also take up space and heat up. what's your advice given the numbers i gave you? thanks.