Heat shouldn't be a problem, the heat sinks are properly sized per the wattage. The multichips are all the same size (30W, 50W, 100W) and yet the floods get bigger per the wattage in order to mitigate the heat.
Multichips are fine, imo. Some people don't like them for various reasons. They do pack a lot of Watts in a rather small amount of space so you tend to get hot spots of light similar to using multiple 600W HPS fixtures, or what have you. When using 1W or 3W chips you can space the LED's accordingly and arguably get more homogeneous light levels over your canopy. I think they are cool because they simplify the DIY process a lot, and if you have multiple wavelengths on the same multichip you get very even spectral mixing by having all the chips so closely packed together. Think Kessil where the light is evenly mixed by the time it leaves the reflector, whereas with 1W/3W LED's you might need the lights at 12in or so before those Blue hot spots that bleach your plants are "diffused" enough to not have negative effects. I guess this isn't really a selling point here considering we're discussing White multichips, but for the record, I guess. Also, most of the multichips you see use Chinese chips so you don't get quite as high efficiency when compared to boutique name brands. When I'm looking for a quality multichip I aim for the Red chips to be 42mil and the Blue chips to be 45mil. If the seller doesn't specify I usually guess they're 35mil and those chips aren't as efficient.
How you know its the real deal and some LED factory is exclusivly producing pcb in low quantity and high quality and very cheap just for u?
You can never know if what you get is the real deal or not, unless you buy it straight from the manufacturer (in this case: Cree).
