The Elitebook 840 supports a 1,600MHz processor memory clock speed which is faster than most notebook PCs of this age and spec. Most notebook PCs of a similar type and age to it support a 133MHz processor memory clock speed. In addition, this HP notebook PC supports 1 and 333MHz processor memory clock speeds.
This portable PC's memory clock speeds supported by processor (1,600MHz) is in fact the best supported memory clock speeds supported by processor across all similar spec laptops that are a comparable age to the Elitebook 840.
A 133MHz processor memory clock speed is the worst supported memory clock speeds supported by processor amongst comparable types of portable PC.