The NP540U4E supports a 1,600MHz processor memory clock speed which is faster than most comparable spec laptops that have been available for a similar time to it. Most medium processor core notebook PCs that were released around the same time as it support a 133MHz processor memory clock speed. In addition, this notebook PC supports 1 and 333MHz processor memory clock speeds.
This notebook PC's memory clock speeds supported by processor (1,600MHz) is in fact the best supported memory clock speeds supported by processor amongst all laptops of this age and type.
A 133MHz processor memory clock speed is the worst supported memory clock speeds supported by processor amongst similar types of notebook PC.