kung upgradeable yung ram, magdagdag ka kahit maging 8gb kasi malakas kumain ng ram yang software na yan tapos may bukas pa na ibang programs, gg talaga yan.
Maghihingalo po talaga ang 4Gb RAM sa Photoshop TS. Try upgrading your RAM or refrain from multitasking. Monitor mo na rin RAM mo kung may mga background apps na malakas kumain ng memory.
Malakas din kumain ng memory ang skype. Much better sa phone ka nalang gumamit niyan.
Also check your battery performance option. Make sure to set to Best Performance kung gagamit ka ng photoshop.
Try to check also kung anong malakas kumain ng memory aside sa photoshop.
Possible din sa preferences ng photoshop mo. Try to limit the memory usage.