[SOLVED] Can I use a new memory stick from a different company with an already existing old one from a different company


Mar 3, 2021
So today I thought of upgrading my dad's laptop (Dell Inspiron 15 3521) cause of its slow speed and boot up, it's current specs are:
4GB DDR3 Ram
420GB Storage (Slim HDD)
Intel Core i5 3317U
Windows 7 Ultimate

I thought of upgrading the windows to 10 and putting a new 240/120GB SSD (IDK which one is more preferable, please help me choose) and another 4GB DDR3 Ram.
The Problem is IDK whether the new DDR3 Ram might be compatible with the already existing one (Despite having the same MHz (1600) the companies are different) So do you recommend me to install, the new one with the old one or get 2 new ones and replace the old one as well?
Well any random ddr3 should just work, more better if the ranks (like 1Rx8 or somthing like that) is identical to the ram you have right now :D

For SSD, Klevv N400 is great, or Team GX2 series is pretty good :D