Minimum FPS is always low, but average FPS is alright

[threelyfours]

So im running a forge modpack with like 160 mods in it and my min fps is always low for some reason, making the game way less smooth, even though my avg fps is alright. And this only happens in my modpack but whenever i try other modpacks who are even larger than mine like better minecraft the min fps doesnt drop as low as mine 

[warjort]

Try this mod: https://www.curseforge.com/minecraft/mc-mods/spark

to understand what is happening.

[threelyfours]

i already have spark installed