I tested building HLODs on a few sizes of Landscapes on my workstation, starting at 2017x2017.
For an 8129x8129 Landscape, at default LOD, it took 30 minutes and required 180GB of memory.
So if you have something like 64GB in your system, a 30GB Page File is way too small, depending on the Landscape size you are trying to HLOD.
For an 8129 Landscape you would require 64GB RAM + 128GB Page File at least.
I have my doubts that a Page File is going to save you, they have limitations.
Plus, if your Page File is not on a PCIe5 NVMe then your performance is going to be horrific.
DDR4-2166 memory is about 40 times faster than an SSD, so what takes 1 minute in memory will take up to 40 minutes or more on a Page File on an SSD.
It took my workstation 30 minutes to build (W7-2495X 24C/48T, 512GB DDR5) so if it paged out you could be looking at as much as 40x as long.
