TMixing different RAM brands and capacities can sometimes lead to compatibility issues, even if the basic specifications (DDR4, 3200MHz, C16) match. Here are some possible reasons why your system isn’t booting:
Even though both your Corsair 16GB and Kingston 8GB sticks are DDR4 3200MHz C16, they might have different sub-timings, voltages, or IC chips.
Some motherboards are picky about mismatched RAM, and differences in XMP profiles can cause instability.
Your current slot configuration is:
Kingston 8GB | Corsair 16GB | Kingston 8GB | Corsair 16GB
This setup means that different capacities are paired together in dual-channel mode, which can cause instability.
Ideally, identical RAM sticks should be paired in alternating slots:
A1 & B1 (for one RAM kit)
A2 & B2 (for the other kit)
Try swapping the order:
Kingston 8GB | Kingston 8GB | Corsair 16GB | Corsair 16GB
If you have XMP enabled, it might be trying to apply one RAM kit's profile to the entire set, which may not work properly.
Try disabling XMP in BIOS and manually setting the speed (e.g., DDR4-2933MHz instead of 3200MHz) to see if it boots.
Some older BIOS versions may not handle mixed RAM well.
Check if you have the latest BIOS for your MSI B450-A PRO MAX.
Test each RAM kit separately to verify if one of the modules is faulty.
Boot with just Corsair 16GB x2 → Check stability.
Boot with just Kingston 8GB x2 → Check stability.
If both work alone but not together, they are likely incompatible.
Try swapping the order: Kingston together, Corsair together.
Disable XMP and manually set RAM speed to 2933MHz.
Update BIOS to the latest version.
Test each kit separately to rule out a faulty stick.
If none of these work, your motherboard or memory controller might not handle mixed RAM well. In that case, using only one RAM kit (either Corsair or Kingston) is the best option.