Kingston HyperX 2 GB (1x2) PC2-64000 CL4 240-Pin DIMM Kit KHX6400D2LLK2/2GR Power supply : Vdd: 1.8V  0.1V, Vddq: 1.8V  0.1V, Double-data-rate architecture; two data transfers per clock cycle ,Bidirectional data strobe(DQS) Differential clock inputs (CK and CK) , DLL aligns DQ and DQS transition with CK transition, Programmable Read latency 3, 4, 5 (clock) Burst Length: 4, 8 (Interleave/nibble sequential), Programmable Burst type (sequential and interleave) Edge aligned data output, center aligned data input, Auto and Self refresh, 7.8us refresh interval (8K/64ms refresh) Serial presence detect with EEPROM, High Performance Heat Spreader, PCB : Height 1.180-Inch (30.00mm), double sided component