After a lot of testing, with different commands. We’ve come to the conclusion that you cannot allocate more RAM/VRAM to Fortnite unlike other games such as Minecraft.
If you are experiencing FPS drops and low FPS then you will more than likely either need to lower your settings. Or if you are already on the minimum settings lower your resolution. If you are playing one 1280×720 on minimum settings and still have low FPS then unfortunately you’re going to have to upgrade your PC.
With the recent release of Chapter 2 we though Epic could’ve added the option to increase CPU cores and RAM. Unfortunately they didn’t although there is a command line argument you can use to allow more cores to be used. Allocating extra RAM will hopefully be an option in the future. Although you’d be better off investing in a better graphics card if you are experiencing low frame rates even on the lower settings.
We’re sorry we couldn’t help you to increase the RAM allocation. However, you can be confident that you don’t have to keep searching for a solution as it is not possible.