Corsair Memory today announced their fastest ever DDR memory module, a DDR550 module that supports very aggressive 2.5-4-4-8 latencies.

These modules typically support 2-2-2-5 latencies at 400MHz clock speeds. The new parts are:
TwinX1024-4400C25 matched pair of 512MB, DDR550, 2.5-4-4-8, black XMS modules
TwinX1024-4400C25PT matched pair of 512MB, DDR550, 2.5-4-4-8, platinum XMS modules
Both these parts are available immediately from resellers worldwide, and are also available as
individual 512MB modules. TwinX kits are tested as a matched pair at their rated specifications
and packaged together immediately after passing test, guaranteeing that the customer
receives a product that has been verified in the dual channel environment. These modules
include Corsair’s classic black or platinum aluminum heat spreaders for improved heat
dissipation.

Source: Corsair