Mushkin 991499 DDR2 UDIMM (2x1GB) 2GB PC2-4200 4-4-4-12 NONE 1.8V Compatible Frequency This product is engineered to operate at the optimum frequency for compatibility with your system. Compatible Timings This product is programmed to use timings that offer maximum compatibility with your system and original memory. Dual Channel Kit Engineered for dual-channel architecture. Type: DDR2 Voltage: 1.8V Speed Spec: PC2-4200 Frequency: 533MHz Capacity Kit Type: Dual Kit Module Size: 1GB Module Build: 128Mx64 Chipset Density: 64Mx8 Timings tCL: 4 tRCD: 4 tRP: 4 tRAS: 12 Cooling Technology Heatsink: None