The motherboard determines both what CPU's are supported and what RAM. So better have a look at the user manual or fact sheet on the MSI site.
Most motherboard perform best with an even number of equal RAM sticks in the right slots. Here also: see the manual or check at crucial.com.
The system requirements for the program you use at https://www.blender.org/download/requirements give 8 GB as recommended and 16 GB as optimal (production-grade). So it's not clear where your 32 GB comes from.
I just purchased an MSI X99A SLI Plus motherboard intending to put an 5820K processor in it but had the opportunity to purchase a Xeon 2670 with 12 cores cheaply. However, I'm not sure whether the application I use (blender) will be able to make use of all 12 cores so it might be that I try it and then sell it again and go back to the original plan of a 5820K instead. So ideally I would like to buy memory that will work with both chips.
First of all my motherboard only supports DDR4 so I'm clear with that. But I've read that the 2600 Xeons only support 2133 Registered memory. If this is the case, can this memory work whith the 5820K processor should I wish to swap?
Second question is how many modules should I buy to get the best performance. I've read that I should fill all my memory slots if using a xeon processor otherwise it might significantly hindered with memory bandwidth. Can anyone know confirm that this is the case? My motherboard has 8 memory slots and I don't really want to fill all of them if I can help it (I only need a maximum of 32 GB and don't really want to buy 8 4GB modules.
Many thanks

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic