Hi! Eric (2010/06/22 13:11), Eric Deis wrote: > Transaction: Address/Command error Its mother board (memory controller) problem. Its *not* DIMM problem.(memtest can't detect this error.) your data transfer(read/write) sometimes met bit errors. This is Nehalem cpu's error detecting feature.(MCE) Try new mother board, or your MB always indicates this error in latest kernel, Its time to buy certified vendors hardware. Supermicro's MB is not certified hardware, but she just indicates hardware problem. Tsuyoshi.