Can't Change RAM In minecraft Forge Server

[GodNox]

So basically i created a normal minecraft server, just a regular survival with friends but then we got bored so i tried making a modded server and i placed a bunch of mods (about 30 40 mods) and every time i start the forge server file (forge-1.7.10-10.13.4.1614-1.7.10-universal) after a minute running it it just getting lower and lower fps. Im Pretty sure da thats becouse of RAM pls welp (btw im playing on 1.7.10 if you havent realised)

[Ugdhar]

1.7.10 is no longer supported on these forums due to age.

In order to receive support here, you will have to update to a newer version (1.12+ I believe)