Corsair announced a new high-end DDR memory module. The DDR550 supports 2.5-4-4-8 latencies with typical latencies of 2-2-2-5 latencies at 400MHz clock speed.
According to Corsair, the models TwinX1024-4400C25 (black) and
TwinX1024-4400C25PT (platinum) were tested on "on a number of 875P, 865PE and 939-pin Athlon 64 FX based motherboards".
More information is available on Corsair's website.