Just yesterday i created a custom modpack for the Technic platform. Regarding matters about the mods, i made sure i had installed every core mod that corresponds to it's specific mod. I made sure the game starts up by firstly running the pack on client and things went great up until i decided to load up a world. Somehow sensing something might just go wrong, i made the world into the superflat type but really to no avail as the problem i expected had not been solved. I experienced massive lag, joining the world took some time and the max frame-rate i could squeeze out is 10-15 FPS although i have good specs on my computer :
Intel Core I3-4170 3.7GHz
2 Sticks of DDR3 4GB RAM
AMD Radeon RX 460
I tried allocating up to 6 GB of RAM, however that still did not manage to solve the issue. RAM usage usually goes up to about 2GB, and Minecraft always allocates 100% of the RAM I have put in, or rather Forge does that. I'm kind of lost as to what the problem could be, so i was looking for some guidance as to what i should do in order to fix it. The modpack consists of 63 mods ( some not showcased in the mods list ) and it's created for Minecraft 1.12.2 .