yeah the BH-5's are good chips, but generally require some high voltages to really juice them of their potential.
Also the 2x256 kits run better than the 2x512 kits as far as overclocking goes.
Do a bandwidth test Ace, and you'd be surprised at how little you lose going from 2-2-2-5 to 2.5-3-3-7 for example.
4W4K3 actually did it from 2.5-2-2-7 to 2.5-4-4-7, from the middle numbers going 2 to 4 he lost like 200mb/sec bandwidth, and from 2-3 it wasn't much.
I got mine running DDR480 at the moment with 2.5-3-3-7 timings.
Got 3655/3372 in the SiSoftware Sandra Memory Benches with that.
I know it can hit DDR250 on these timings, but I don't think my mobo wants to do it, although Mike9872 whatever those numbers were lol, got 250 working on his NF7