Difference between the WD hard disks?

[wsh]

Does anyone know what is the difference is beween the

WD10EACS
http://www.overclockers.co.uk/showp... Green 1TB SATA-II 16MB Cache - OEM (WD10EACS)

and

WD1000FYPS
http://www.overclockers.co.uk/showproduct.php?prodid=HD-182-WD&groupid=701&catid=14&subcat=940