[SOLVED] Mixing memory question?

[MeeLee]

Hi!
I got a Core i5 9400f, running 2 sticks of 4GB 2400Mhz DDR4 in dual channel mode (slot B1 and B2).
I have slot A1 and A2 available.
I was wondering what would happen if I would plug faster, or slower memory in slot A1 and A2?
Does the system still run the memory in 2x dual channel mode (not equal quad mode), or does it undo dual channel mode, and runs it in single channel mode; or does it run the memory in quad mode at the slowest memory settings?

I need the extra memory to load a heavier program, but only have 2 RAM speeds to choose from for slots A1 and A2: (3200Mhz + 2400Mhz, or 2100Mhz + 2400Mzh)

 

[rgd1101]

mixing ram sometime work, sometime don't.
mixing speed less chance of working. and it will run the slowest compatible speed

 

[MurdyPlay]

sure you can do it, why not?