What happens when I use different memory capacities in dual channel

[Thameem97]

Let's suppose there's the following configuration
One pair of slots on a dual channel is of matched 8gig cards ( total 16gigs ) and the other pair of slots is used by a matched pair of 4gig cards
What exactly will happen ?
Will my memory not be as it should be ?

 

[VicVega1]

You'll never know till you try sometimes it works, sometimes it doesn't (usually doesn't). Motherboards are very picky these days and it's best that you use the same sticks (same capacity, voltages, timings) in all slots.

 

[Tradesman1]

What mobo and CPU? If the two sets will play together (they might not) then if the mobo is fairly recent, it will prob support Flex mode if Intel, or AMDs version of Flex and all 24GB will run iin dual channel (12 GB in each channel) - if problems getting them to play give me a shout 😉