RAM - Do they have to match?

[Hi P]

1.- What happens if you use RAM from different brands but same frequency?

 

2.- What if they are the same frequency but different latency?

 

3.- What if you use RAM from the same brand with the same frequency and latency but different model?

 

3.- Do you always have to match your RAM by brand and part number?

 

Thank you

[Cereal5]

RAM will run of the slower of the two speeds, and I believe at the slower of the two latencies as well (correct me if I’m wrong here). You don’t HAVE to match your RAM, but it all but eliminates the possibility of compatibility issues if you do, so that’s why it’s recommended you match it, but not required.

[peacefulpolarbear]

1. This will be fine, but isn’t guaranteed

2. Both the sticks will run at the slower latency. Also isn’t guaranteed.

3. This is fine but also not guaranteed to be problem free.

3. You should try to if possible 

[Milkcrate336613f]

It certainly can cause instability but many times the two sticks will simply run at the lpwest ones ratings in both speed and latency. Im in between upgrades on a server/gamer system atm and while I am waiting to get 2 budget 3000mhz ddr4 sticks i attemped putting ome g. Skill aegis 8gb 3000mhz with cl16 1.35volt in with a Corsair vengeance 2400 cl 16 1.2 volt. They not only worked but still managed dual channel. I middle grounded and am running stable with both at 1.22volts and 2800mhz timing 16-18-18-39 or something to that aprox. Ive also mismatched ddr3 many times without issue in both desktops and laptops. Never had an issue so far. The onlyone ive yet to test is a thing called something like assymetrical dual channel. Its basically matching a 8gb stick with a 4gb and the first 4gb on each can sometimes dual channel as well leaving 4gb for extra if needed in single channel. Hope this helps and I will end by still adding discretion as it doesn't have any guarentee to work let alone dual channel it still comes down to chipsets, SoCs, Motherboard support, etc. Always try to find a matching stick and if you absolutely can't try to at least get the timing and frequency the same or as close as possible to ensure better odds of compatibility. 

[Lord Letto]

2 hours ago, Milkcrate336613f said:

The onlyone ive yet to test is a thing called something like assymetrical dual channel. Its basically matching a 8gb stick with a 4gb and the first 4gb on each can sometimes dual channel as well leaving 4gb for extra if needed in single channel.

I believe that's called Flex Mode: https://www.intel.ca/content/www/ca/en/support/articles/000005657/boards-and-kits.html#flex

something that I'm possibly going to try depending on direction I plan on going with RAM, I got a 4GB stick of 2400MHz to start with & debating on getting another 4GB 2400MHz stick, a 2x4GB kit of 3000MHz to replace the 4GB 2400MHz stick or get a 8GB 2400MHz stick to pair with my 4GB stick for 12GB total.