Upgrading memory/ram

[Mareks]

I'm currently using a Dell Inspiron 3847:

 - Intel Pentium G3240 3.1Ghz

 - Zotac GTX 1050Ti 4GB

And I was thinking of upgrading my RAM from 4GB(DDR3 1333Mhz) to 8GB(DDR3 1600Mhz), probably buying 2x4GB.

Is there anything specific I need to look out for when buying memory - I read that voltage and something called "Ranks" play important roles aswell, but a friend of mine told me the only things that matter are Clock speed, CL.

So I'm asking here for some clearance on this theme.

Where does the voltage matter?

If I put in new RAM can the voltage differ(1.35V) from the voltage thats currently in(1.5V)?

And whats up with the Ranks, where does 1R and 2R matter?

I'm not really well informed about RAM so I'm happy about every response

 

 

[MVPernula]

The easiest thing you can do is basically looking up your motherboard and look for supported ram on it.

[Cyracus]

Depending on what your motherboard is you're gonna want ddr3 or ddr3L memory modules, speed isn't a huge deal with intel unless you're using onboard graphics, so don't worry too much about that. ddr3L is low voltage ddr3 ram, may be 1.25v or 1.35v and the 1R/2R is the command rate it's not a big concern unless you're out for benchmarking glory

[Mareks]

The memory that I'm currently using is 1.5V(DDR3)

I'm currently looking through the crucial site & their listing of memory, and the sticks compatible are CL=11. Would the sticks still work if I add sticks that are CL=9/10?