RAM compatibility?

Question

Iron

Good afternoon, I'm going to buy a laptop (Acer Aspire A315-41G-R8PF [NX.GYBER.064]) and immediately insert a 8 gigabyte RAM chip (initially in model 4). And after reading a bunch of articles in order to straighten his brain, he finally broke it.
Sobsna, questions:
1. I met several times that for greater efficiency the dice should be the same - it means that both ddr 4, or does the size still matter
2. Do you need to look at the required frequency on the motherboard bus through the utility?
Thanks in advance, I'm weak in hardware - if I figured out the processor and video card, then I died out in the intricacies

Answer 1

Do you want to add another 4G bar to 8G, or insert a new 8G to replace the existing one?
And how many slats are there now? How many memory slots are there? And what is the maximum amount of memory this laptop supports? (didn't find it quickly)
The standard approach "at random": stuck - started - take, no - return.
And 2 bars or one - on this laptop you will not feel the difference in speed.