New Ram not working

[Ar2008]

So originally in my computer I had DDR4 Trident Z RGB(2x8) 3200mts, but I wanted an upgrade so I got Crucial DDR4 Pro(2x16) 3200mts, I thought this should work no problem, but I was wrong when I add the new sticks in the slots used by the old ram or even different ones my computer does not boot up, but then when I try it with the old and new ram it boots right up no problem. What I’m trying to figure out is why? And why won’t just the 2 new ones work? I checked to see if all 4 slots are actually being used with all 4 plugged in and it says all 4 DIMM slots are being used, so what could be the problem? I also already have tried a CMOS reset to no avail.

[vanpuffelen]

It could maybe be a voltage difference between the two kits, as I've had issues with a Corsair Vengeance 2x8GB DDR4 3600 kit due to it running at 1.35V (default voltage was 1.20V). What are the voltages of the two kits?

[OddOod]

Welcome to the forums!
That's.... VERY weird.
What are the part numbers for the two RAM kits? And what are all the parts in your system? 

[Tetras]

1 hour ago, Ar2008 said:

but then when I try it with the old and new ram it boots right up no problem.

What is your PC?

 

It sounds like you have a PC older than 10th gen?

[2dfx]

16 hours ago, Ar2008 said:

So originally in my computer I had DDR4 Trident Z RGB(2x8) 3200mts, but I wanted an upgrade so I got Crucial DDR4 Pro(2x16) 3200mts, I thought this should work no problem, but I was wrong when I add the new sticks in the slots used by the old ram or even different ones my computer does not boot up, but then when I try it with the old and new ram it boots right up no problem. What I’m trying to figure out is why? And why won’t just the 2 new ones work? I checked to see if all 4 slots are actually being used with all 4 plugged in and it says all 4 DIMM slots are being used, so what could be the problem? I also already have tried a CMOS reset to no avail.

We need more information. What motherboard do you have?  What CPU?