Mmmm what Platy said ! ...

BUT usually this setting is controlled by a catch all in bios like use 'normal', 'fast' or 'fastest' in the memory timings setting in BIOS, this sets other stuff too... You want a DMI tool specifically for your bios to change just this setting, though I wouldn't be paying ANY attention to this at all as Sandra rarely gets any of the more 'exotic' chipsets right (so anything that's not a 440 bx or tx chipset !), if the machine seems to be okay I'd be leaving well alone........

Perhaps a motherboard updated bios might be the first step...?