Hi,
Standby and Suspend are two different low-power modes. Check this wiki pages:
http://processors.wiki.ti.com/index.php/AM335x_Power_Management_User_Guide
http://processors.wiki.ti.com/index.php/AM335x_Linux_Power_Management_User_Guide
http://processors.wiki.ti.com/index.php/AM335x_Power_Management_Standby_User%27s_Guide