Interesting thing I’ve noticed is when I install spongeforge, the RAM usage goes up by 5% (1.6gb) from my 32gb ram total. Note: Only allocated 3gb total to the server.
Other mods/plugins I have are: Worldedit for forge, Pixelmon 5 beta9, Nucleus, VoxelSniper
Is this supposed to happen?
i think it is, beciuse the project isn’t a custom minecraft like spigot, it uses the nornal minecraft server + sponge api + forge api. that means that there is more code loaded and processed for each tick. another thing to remember is that sponge isn’t production ready, higher memory usage or problems with the software can appear more often then relase ready projects.
Wut… Sponge is in no way connected with spigot. They different platforms
It does not use the “spigot” (aka bukkit) API. It only uses the SpongeAPI (and in addition SpongeForge makes use of Forge). It will probably tax a bit more RAM than a plain Forge server initially, but remember you have config options at hand for optimising a server that aren’t available without Sponge.
oops, 
i have some problems with switching platforms. i have edited it
Why would you have allocated 3G to a server when Pixelmon already requires more than half?
As for RAM usage, without a /sponge timings we cannot ascertain anything of the sort. Memory goes up depending on the activity level of a server, so in this case, you could be doing something that ups it. And even then, 3G is not a lot by any standards.
https://timings.aikar.co/v2/?id=d2fb1d28996e438696a1108a2012fed7
This is just a small test server and no one’s really on
isn’t a custom minecraft like spigot? wut?
What do you mean? Spongeforge works like another Forge mods - you can think of it as a bridge to Sponge plugins. On the other hand, Spongepowered also develops SpongeVanilla, which is independent from Forge and (I believe) works like Spigot in that sense. You can find information here: https://docs.spongepowered.org/master/en/ .
What I think he means is that Spigot is a single jar that contains an essentially unseperable minecraft server within it, and that Sponge is different to Spigot as it either used as a Forge mod (SpongeForge), where Forge is a wrapper around the vanilla jar, or Sponge is directly a wrapper around Minecraft (SpongeVanilla). He was just stating the difference between how you use them.
So, Spigot is in that sense a custom Minecraft jar, and Sponge is a minecraft wrapper - but also, in the grand scheme of things, it doesn’t matter, it’s just two ways to achieve a similar goal.
To answer the OPs question on RAM, I think @Rasgnarok hits it on the head. You’re not comparing like for like, because Pixelmon 5 is much bulkier than Pixelmon 3.5, so you have to account for that too - in fact, I wouldn’t mind betting that’s why you’re seeing high memory usage rather than Sponge.
Actually, that’s not quite true, whilst there are added entities, 4.X should actually only require the same, if not less RAM, as opposed to the Vanilla game which went from 500MB being good to 1GB being iffy
exactly what i did mean.