Using just 2n2222s and a 68ohm resistor on each of the base pin, it pulls just under 2 amps when cold.... and sadly even when warm, it still pulls around 2amps! - i've only had it running for about an hour tops so hopefully it gets brighter as it gets hotter lol (68ohm resistors to the base, and no current limiting resistor either on the emitter or collector, they are all sinked via an NPN)
This was simply a test to see what happens if you supply rougly 120ma to each RGB segment of the LED and when it got hot, would it rise to say 200 or even 300ma?... sadly not and if did, it has 200ma of leeway.
either way, it's damn bright for 20watts and hopefully Mr Grumpy is right about high powered LEDs increasing in current when hot because it'll only get brighter and stay well within the 800ma spec limit of the 2n2222's .