Memory - Mixing ranks, good or bad?

[AdrianH]

New PC box came today. Need to buy a 2nd 16GB SODIMM 3200MHz so the total RAM is 32GB. The motherboard has two SODIMM slots with max 64GB Ram supported.

The memory inside is a single module

SK Hynix 16GB 3200MHz 1Rx8, which I understand is single rank, so single row of 8 x 2GB chips.

I can get some more SK Hynix but the actual module is slightly different.

SK Hynix 16GB 3200MHz 2Rx8, which I understand is dual rank, so two rows of 8 x 1GB chips.

PS: There seems to be a lot of misinformation where people are saying it has to do with physical chips on one side or both sides, but this seems incorrect as pointed out by some.

Anyway, question is if I can mix them? Will it cause performance problems? So below:

1) Buy same brand, capacity and speed, but different rank config.
2) By different brand but same capacity, speed, and rank config?

Which is better option?

 

[Lupus]

You can mix them but there maybe a performance hit, how much who knows.

 

[DrJohnZoidberg]

Depending what you're doing on the PC I doubt it will cause any noticeable performance issues, however you may have a hard time getting the overclock to stick on both as the timings are potentially different too. You may end up just running them at 2133Mhz for stability.

Again, depending on what you're doing that might not be a problem and you'll likely benefit more from just having more memory.

If you really want to not worry then just buy a matched 32GB kit and sell the 16GB module.

EDIT: You'll actually see a performance increase when moving to 2 sticks regardless of the rank. I would still chose getting a matched kit though (I've recently just done this myself)

 

[ScottulusMaximus]

Linus did a video on this single and dual rank thing

 

[ponder]

Why don't you buy the same part number?

Post a clear pic of the label here.

 

[The_Ogre]

PC box? As in desktop? You need to check whether it actually uses SODIMM's as SODIMM's are mostly used in laptop PC's.

 

[Mystic Twilight]

Shouldn't really matter with mixing and matching unless your memory controller is super finicky. Ideally you should get two modules of 2Rx8, so that you get the advantages of dual channel and memory interleaving.