Here is a powerful and efficient boost driver (check this Testing boost drivers' thread). Comes stock set at 4.8A in “turbo” so more ;-) brightness (3A version available in store).
Current H1-A is reported to be downgraded 
(smaller inductor), and loses efficiency. Bad choice, CDM, very bad.
I look for high quality lighting in XHP50s (high CRI). I don't care about 3V XHP50.2 variants thus.