Yes, the same amount of RAM is needed.
Yes, the same amount of RAM is needed.
Consider placing the 16G sticks together in the same channel. Right now you have 16+8+16+8, which is decent for performance but could fail sometimes. Try 16+16+8+8, though this may sacrifice performance but might offer better compatibility. If you're not sure about XMP, the simplest option is to reset CMOS. By default it's off. After verifying the sticks function properly, you can turn XMP back on or adjust speed and timing manually. XMP essentially overclocks the system, as defined by the manufacturer, and is generally safe, though mixing different sticks can lead to issues.