ram ddr 3 2 +4 gb supportive in pc

[dinesh.kcvani.dev]

My pc is old duel core.
But ram slots r two, i use only one slot of 2gb now i want increase ram speed so my question is can i use two deffrent speed ram in my pc.
Ddr 3 2 gb old
+ ddr 3 4gb new 240 pin
?

 

[CountMike]

No guarantees but if they do work, they'll work at speed of slower one.