Ram diferences in old laptop

chiriks

Honorable
Dec 26, 2013
7
0
10,510
In my old laptop i have 2x1gb 2Rx8 PC2 5300S-555-12-E3
I got 2gb 2Rx8-6400S-666-12
If i change one of the ram with this 666 is it better works or better just dont change anything?

And if i change one of them which i need to change 1. Which is close mb or or farther?

Sorry for my english.
Thanks for help.