Incompatible RAM? Why?

[CHOCOLATExPANDA]

I don't get it. I've built a few (only a few!) PCs. How could it be that two of the same chip-set RAM sticks (both are DDR4) that even also have the same RPM (2400 RPM) be incompatible? This doesn't make sense to me. Is this a bug, or am I just uneducated about another requirement? Please help!

[GenerallyThrawn]

The game is programmed so that ram sticks must be the exact same as each other to fit into a motherboard. For example a pair of Team Group ram with a frequency of 2400 with 8gb each are compatible, while if 2 Team Group ram sticks were both 2400 but had different capacity, they would not fit together. While this may be different from real life, it is how the game is programmed.

[Stungun]

Please note that the game doesn't require RAM to be identical on ALL merits -- you can mix and match RAM of different brands as long as it's the same vendor, size, and speed (e.g. G.SKILL Flare and Ripjaws memory works together). And obviously RAM that comes in multiple colors or colored LED options (such as Team Group's memory offerings) will work together if the vendor is the same.

Yes, this is one completely unrealistic element of the game. In reality, you can mix and match RAM speeds, brands, and even sizes to your heart's content -- it will just perform sub-optimally.

Here's how it works in reality from what I've read:

Mix and matching RAM sizes in reality will mean that part of your memory won't be in dual-channel mode (except in certain situations, namely 2x(something) + 2x(something else). Say you combine a 4GB and 8GB stick (with the sticks in separate channels), the first four GB of the second stick will be in dual channel mode with the 4GB stick but the last four GB of the second stick will be in single channel mode since it has no corresponding RAM to be paired with. However if you have each channel containing a 4GB AND an 8GB stick it will work in dual channel mode without a hitch.

Mix and matching RAM speeds will (usually) just run at the slowest clock speed.

Mix and matching brands, I'm not so sure on, but it's theoretically doable and people have done it before without problems.

However, in reality there is a small chance of sticks from different kits -- even with the exact same timings, speeds, sizes and brands -- to not work together properly (either causing the system to fail to boot, or causing stability issues).This is because for RAM kits you buy, the modules are tested to work together as part of quality assurance. So it's always the most ideal to just buy all your RAM together in a single kit and install it all at once, but IRL there can be situations where it may be necessary to mix and match, such as being on a budget or cannibalizing parts from other computers.

Considering PCBS already simplifies a lot of real world elements, it really doesn't make sense to place this arbitrary restriction on RAM. I'd suggest that mix and matching RAM should be changed so that different brands work together (or maybe sticks have an invisible built in variable that can make them not work with certain other brands, being set stick to stick like with component overvolt tolerances -- and maybe mixed RAM incurs a small, arbitrary 3DMark performance hit), different speeds should be able to work together but will disable XMP auto-overclocking, and different sizes should work together but disable multi-channel mode if the channels are uneven.