The best we could squeeze out from our kit of bad kingstons was 2300mhz with ugly latencies and by putting ram kit@ln2... we tried also to use a lower bclk and the 2400mhz divider to have a resulting frequency of around 2300mhz, no post at all.
Massman just told me on hwbot forums that the 2400mhz divider was available only on es cpus, so that is why there's no luck in trying to use it