Question upgrading ram question

My 6 year old custom built rig has 16GB HyperX FURY DDR4 2133MHz (4 x 4GB).
Would i gain anything by using more ram and ram of a higher MHZ.
The ram i have been looking at is 32GB Kingston FURY Impact DDR4 PC4-25600 32OOMHz SODIMM.

I have copied this description from another website

Ready for AMD Ryzen and Intel XMP-ready in capacities of up to 64GB, Plug N Play FURY Impact DDR4 automatically overclocks to the highest frequency published, up to 3200MHz, to support Intel and AMD’s latest CPU technologies. Slot in the sleek black PCB for a hassle-free boost, no need to tinker with the BIOS. Upgrade your system’s performance and still run coolly, quietly and efficiently, thanks to FURY Impact DDR4’s low 1.2 voltage.

My mobo is a ASUS® ROG STRIX X99: ATX, USB 3.1, SATA 6 GB/s. ROG STRIX X99 GAMING | ROG Strix | Gaming Motherboards|ROG - Republic of Gamers|ROG Global (asus.com)

As i will be going from 4 sticks to 2 , i have read that to work properly in dual channel you have to use the outer most ram slot , miss one and use the net one so i guess that means slot 1 and 3
 
My 6 year old custom built rig has 16GB HyperX FURY DDR4 2133MHz (4 x 4GB).
Would i gain anything by using more ram and ram of a higher MHZ.
The ram i have been looking at is 32GB Kingston FURY Impact DDR4 PC4-25600 32OOMHz SODIMM.

I have copied this description from another website

Ready for AMD Ryzen and Intel XMP-ready in capacities of up to 64GB, Plug N Play FURY Impact DDR4 automatically overclocks to the highest frequency published, up to 3200MHz, to support Intel and AMD’s latest CPU technologies. Slot in the sleek black PCB for a hassle-free boost, no need to tinker with the BIOS. Upgrade your system’s performance and still run coolly, quietly and efficiently, thanks to FURY Impact DDR4’s low 1.2 voltage.

My mobo is a ASUS® ROG STRIX X99: ATX, USB 3.1, SATA 6 GB/s. ROG STRIX X99 GAMING | ROG Strix | Gaming Motherboards|ROG - Republic of Gamers|ROG Global (asus.com)

As i will be going from 4 sticks to 2 , i have read that to work properly in dual channel you have to use the outer most ram slot , miss one and use the net one so i guess that means slot 1 and 3
Your going from quad channel to dual channel.....that's a negative.
Your going from 2133 to 3200....that's a positive.
Add the + and the - and what do you get?
You'll find out after the swap.

Adding ram.....if your not using all the ram you have now adding more won't do much for you.

Which slots to use?.....look in the manual there might be a pic.