Nope, as there are no guarantees when mixing packages of DRAM, if it was as easy to mix as many want you to believe the makers would simply sell single sticks and make more money - they test sticks to pair up ones that will play before packaging. You can pull twopo sticks right off an assembly line and they might or might not play.
Yes, one of my PCs has 2 x 2 and 2 x 4 without an issue. They don't even match in voltage or speed, not sure about timings. I wouldn't worry too much. check to make sure the 16GB sticks are not dual rank. If they are, you might run into clock speed issues.
Apr 26, 2016. #2. In reality, mixing brands of DDR memory can cause problems in some situations. While each manufacturer is supposed to use the same standards, each one has their own spin on the DDR memory protocols. These minor differences can cause operational problems when you start mixing different brands.

If you want 16gb go for 2 8gb modules. That way you take full advantage of the dual channel architecture. On topic though the extra 4gb probably wont be of any use to you. Plus if the new modules are different speeds to the one you have they will all run at the slowest speed. Ie. 2x 8gb 3200 and 1x 4gb 2666 they will all run at 2666mhz.

In other words, if you have an 8 GB stick installed, it is recommended to get another 8 GB RAM stick instead of 4GB to match the size. Also the choice of the RAM slot also matters to ensure that RAM sticks work in the dual channel mode. Generally, you should plug the sticks in alternate RAM slots and you should always have a pair of them.
What is a 1rx8 ram stick… what is a 2rx8 ram stick.. these are not normal terms used to describe computer memory. Usually when describing RAM for compatibility reasons, they are described by Size, Speed, and Type. So, in my computer, I would say, I have 2 sticks of 16gb 3200Mhz RAM no clue what you’re description about the RAM you have means.
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can you mix 8gb ram with 16gb ram