You need more than 3.3v's to really push BH5..the sticks are prolly warranteed upto 3.3v's but they clock the best with 3.7 or so.
You must have a fan blowing over the ram/ timings in bios set to 2-2-2-5 1T cause that's what BH5 is made for.
I have had tons of BH5 sticks, the best ones did 2-2-2-5 280Mhz @ 3.8v's