HP ProLiant ML350p Gen8 memory upgrade

[obejo]

Hello,

We own a HP ProLiant ML350p Gen8 server wich has 32 GB memory (8x4GB).
See the positions below:

here

I want to upgrade the memories and i have got more 1x16GB.
If i had 2x16 GB then i would set in mirror on the two processors, but since i have got only one i dont exactly know how to set up them (8x4GB + 1x16GB) in order to get the best performance.
Someone who is more experienced in this please help me.

Thanks a lot.