Questions
Q1
Why my A88MD cannot support DDR3-2400 speed?

A88MD will support DDR3-2400 speed by overclock the memory frequency.

If motherboard cannot boot up with DDR3-2400 speed, or system unstable.

Please try to change CPU or memory module on the system.

Because either CPU or memory module might not good enough for support DDR3-2400 speed.