Mushkin Enhanced 4GB DDR2 800 (PC2 6400) ECC Fully Buffered Memory For Apple Mac Pro Model 971609a Type: 240-Pin DDR2 FB-DIMM Compatibility: For Apple Mac Pro System Cas Latency: 5 Timing: 5-5-5-18 Voltage: 1.8V Heat Spreader: Yes Parts: Lifetime limited Labor: Lifetime limited