I am using this 10 W RGB LED, unfortunately DX does not provide a datasheet for it. I don't know how efficient these power LEDs are... so approximately how much applied power is converted into light and how much is dissipated as heat? Almost all 10W is dissipated or only small portion of it?
As there is no datasheet, I even cannot compute the required heat sink, so it seems I need basically to try :) Unfortunately I don't have any heat sinks at home, only one from old VGA card (which is 74 x 94 mm with 12mm high fins, but half of the surface has place for a fan, so no fins there). Do you think this is an overkill for my LED? I have no idea for how big heat sinks should I look. The LED itself is on a metal plate which is 14 x 22 mm, so the heat transfer from LED to heat sink should not be a problem.