Crucial 4GB (1x 4GB) DDR2-667 PC2-5300 1.8V DR x4 ECC Fully Buffered 240-pin FB-DIMM RAM ModuleProduct Overview Dramatically improve performance and handle larger user and application workloads in your mission critical workstations and servers with this 4GB (1x 4GB) DDR2 667 MT s 240 pin FB DIMM RAM module from Crucial . This Dual rank, x4 configuration RAM module is for use in DDR2 compatible systems and operates at 667 MT s with an overall transfer rate of PC2 5300. This RAM module also operates at a standard voltage of 1. 8V and is designed