Adding different ram modules

[ArmasF32]

So i have 16gb DDR4 Ram 3000mhz ram in my system (see my build), i want to add some more memory, but more likely 1x/2x 8gb DDR4-3000 Corsair Vengeance. Will that hurt the performance/will it be at its best potential or would i need another 16GB DDR4-3000 Corsair Vengeance?

 

 

[Analog]

That original memory is it 3000MHz JEDEC or with DOCP / XMP? If it is JEDEC then it probably will work with the new memory, considering that is also 3000MHz JEDEC. If one of these kits or both of them are 3000MHz only with DOCP / XMP enabled, then who knows. You might not be able to get them to run at that speed or it can all be absolutely fine. The best thing is to try and find an exact matching kit by part number to the one you already have. This way you will probably not have any issues. 

[Rym]

As long as ALL timings and subtimings are the same, it "should" not be a problem. Especially without OC.

[Eigenvektor]

Mixing modules should work, but there's no guarantee. If you go with 1x you'd lose dual channel though. For that you need either 2 or 4 modules.

 

As @Analog said, overclocking (XMP) with mixed modules is more likely to have issues (also 4 sticks is more likely to have issues than 2). If you combine multiple different sticks they will run at the lowest commonly supported speed and highest commonly supported latency in any case.

 

~edit: Do you have 1x 16 GB right now or 2x 8? Because that would mean you're running with single channel speed and another 1x 16 GB to get dual channel would be ideal for performance.

[Moonzy]

47 minutes ago, Eigenvektor said:

Mixing modules should work, but there's no guarantee. If you go with 1x you'd lose dual channel though. For that you need either 2 or 4 modules.

Not quite, you'll still get dual channel bandwidth for the first x amount of gigabyte, where x is double the amount of the lowest memory in any channel

ie, (8+8) + 8 = 16(dual) + 8(single)

 

It's called flex mode

 

U can also mix 16 + (8+8) to achieve dual channel, from what I understand

[Eigenvektor]

2 minutes ago, Moonzy said:

Not quite, you'll still get dual channel bandwidth for the first x amount of gigabyte, where x is double the amount of the lowest memory in any channel

ie, (8+8) + 8 = 16(dual) + 8(single)

 

It's called flex mode

 

U can also mix 16 + (8+8) to achieve dual channel, from what I understand

You're right. I didn't mention it because I think you need support from the CPU and motherboard for this which isn't always a given. I remember people mentioning this was only really a thing on Intel, but maybe this has changed. Personally I'd rather go with 2x8 or 2x16 instead of relying on flex mode.

 

For the sake of completeness: Dual channel mode for DDR, DDR2, DDR3 and DDR4