What does this modpack need to run?
Search a CurseForge pack and get the four things that decide whether hosting it is an afternoon or a weekend: its Minecraft version, its loader, the Java that pair needs, and whether the author ships a server pack at all.
About the memory figure
CurseForge publishes no memory requirement for modpacks. There is no such field on the pack, on its files, or anywhere else in the API — so every site that shows you an exact "recommended RAM" for a pack has either lifted it out of the author’s description or made it up. The figure here is ours: an estimate from the pack’s installed size against the same model as our RAM calculator, and it is labelled as an estimate wherever it appears. Treat it as a starting point, then watch what the server actually uses.
Why the server pack matters more than the size
A server pack is a separate download the author prepares containing only what a server needs. When one exists, hosting the pack is unzip and run. When it does not, you assemble the server side yourself — and the awkward part is that client-only mods do not get politely ignored on a server, they crash it on startup, one at a time, so you find them by elimination. A pack with no server pack is a materially bigger job than one with, regardless of how large either is.
The Java version is not the pack’s choice
It follows from the Minecraft version the pack targets, which is why we can state it exactly rather than estimate it. A 1.20.1 pack needs Java 17 whatever its author wrote; a 1.21 pack needs Java 21. Getting this wrong is the most common reason a correctly assembled pack refuses to start, and the error names a class file version number rather than a Java release, which sends people looking in entirely the wrong place.