Dell Precision 3630 tower 16 x 2 + 32 x 2 GB RAM Configuration is allowed? [duplicate]

I have a Dell Precision 3630 tower with an Intel i7 8700 processor (Intel C246 chipset). The PC also has NVIDIA P1000 4 GB GPU.

Among the four DIMM slots, two are populated with 16 GB DDR4 2666 MHz RAM.

Can I now add 32 GB x 2 RAM in those two empty slots to make it a total of 96 GB RAM? Also, if it possible to have (16GB x 2 + 32 GB x 2) combination, is it possible to add those 32 GB RAMs with 3200 MHz or it is mandatory to use 2666 MHz 32 GB RAMs in the present configuration?