Question RAM not working with new Mobo

[andypta0401]

I have 2 RAM sticks: 4GB and 8GB, 2400MHz, both worked well with my old PC: A320M-A10-9700+iGPU
I've just upgraded to B450m Ds3h +Ryzen 5 2600+Rx570> only the 4GB works, the 8GB is dead now and i have no idea why
Does anyone know what's wrong with it? I think it could be a bad RAM but i cant test with another PC.
Plus when i put both in the slots and open Task manager > 12GB RAM (8.1 GB hardware reserved) or 3.5 usable.

 

[LordVile]

I have 2 RAM sticks: 4GB and 8GB, 2400MHz, both worked well with my old PC: A320M-A10-9700+iGPU
I've just upgraded to B450m Ds3h +Ryzen 5 2600+Rx570> only the 4GB works, the 8GB is dead now and i have no idea why
Does anyone know what's wrong with it? I think it could be a bad RAM but i cant test with another PC.
Plus when i put both in the slots and open Task manager > 12GB RAM (8.1 GB hardware reserved) or 3.5 usable.

You shouldn't be using mix and match with Ryzen and it's too slow for it too.
Check the board compatability list