lomapaseo,
If you're talking about USB devices, then yes, its a well known fact that the motherboard produces a finite amount of current on the USB ports (the exact amount varies by manufacturer). It is also a well known fact that on some motherboards some ports are high draw and others are low draw, and if you happen to plug a high draw device into a low draw port, you won't see much.
If an optional external power adapter is available for your caddies, try that. Otherwise a powered USB hub. Quite honestly if your caddies are for 2+ drives and you've got drives in all the slots, you would be better off with external power adapters anyway.