Can I upgrade my RAM from 32GB to 64GB by using only 2 RAM slots?

XPS 8930 supports up to 16GB per slot, so you have to go with 4x16GB for 64GB total. Also supports DDR4 RAM and I am not aware of any DDR4 RAM that comes in 32GB modules . . . that would be DDR5.

EDIT: OK, I found some DDR4 32GB RAM modules, but I don't think they would work in the XPS 8930.

@ProfessorW00d​ Crucial by Micron makes DDR4 RAM 2x32GB. https://www.newegg.com/crucial-64gb/p/N82E16820156327?Item=N82E16820156327

I haven't opened the packaging yet in case I have to return it. So it looks like it won't work as each DIMM slot is limited to 16GB max. I'm confused by this post why it said to use DIMM 1 and 3:

https://www.dell.com/community/en/conversations/xps-desktops/xps-8930-memory-upgrade-from-16gb-to-64gb/647f7819f4ccf8a8de626b50

@JAYRULE​   I think the note would mean if you are only using two modules, which could give you a maximum of 32GB . . . don't install those in slots 1 & 2, for example.

I don't think they were making 32GB RAM when the XPS 8930 came out, so it may be that it is just not tested and verified by Dell. Also, I don't know if the i9-9900K processor has any limitations of this sort.

@ProfessorW00d​ In your opinion, do you think it will work if I tried installing it or do you think I should just return it before destroying the packaging? 

@JAYRULE​   I cannot say for certain, but I lean toward 'not working'. If you do decide to try, let us know how it works out.

@ProfessorW00d​ Thanks for all of your input and time. I'm going to just return it back to Newegg because it looks like no hassle return like Amazon. I should've done more research on the RAM capacity but now I know. When there is another sale, I will order the 64GB (4x16GB) version. Since I'm a Youtuber, I usually make a video of how to but I have a feeling this time it won't work so I'm not going to even bother having to disconnect everything and opening up the pc, reboot, etc...

@JAYRULE​    good idea . . . you know for certain you can get 64Gb with 4x16GB

officially the processor can accept 64 GB per stick.  The motherboard may lockout anything above 16, and Dell never tested anything above 16 GB. 

Honestly, if you do 2 x 32 make sure it's dual-ranked DIMMs and if you are doing 4x16 make sure they are single-ranked DIMMs.  That way you do not overload the memory controller.  Since it can only read one rank at a time, even on dual-ranked setups.  Just 2 DIMM x larger capacity is easier on the controller than populating all 4 slots.  Some systems can become unstable with 4 DIMMs slotted.