Trying to figure out the source of game stuttering. Advice?

[MechanosG]

I've been testing the viability of a 1.16.5 modpack centered around Dynamic Trees, that can keep enough FPS that a mid-range or older potato computer can still run it. I don't have many mods added yet (about 50, most of them performance/tweak mods), and have been jumping back and forth testing between Halogen and Performant (but not both at the same time). When I use Performant, I get about 25-30 FPS in a heavily wooded area. When I switch to Halogen and load the exact same world, my FPS doubles depending on which direction I look, getting 30-60 FPS. However, when using Halogen, I often get random game stuttering every couple seconds or so, where FPS hits 0 for a moment then returns. It's bad enough that's it's very noticeable and affects gameplay. Performant doesn't seem to have this problem so far though (I plan to test it more to make sure). There are several comments on the curseforge page mentioning the same problem too, but none elaborating on a specific cause or fix - just that it happens when they're using Halogen.

Does anyone have any ideas about what could cause this, and how I should go about seeing if there's a config/setting to fix it?

Mods list

AI-Improvements-1.16.2-0.3.0.jar
appleskin-forge-mc1.16.x-2.1.0.jar
AutoRegLib-1.6-49.jar
betterbiomeblend-1.16.4-1.2.9-forge.jar
BetterMineshafts-Forge-1.16.4-2.0.4.jar
Clumps-6.0.0.27.jar
comforts-forge-1.16.5-4.0.1.3.jar
Controlling-7.0.0.26.jar
CraftTweaker-1.16.5-7.1.2.451.jar
create-mc1.16.5_v0.3.2d.jar
CTM-MC1.16.1-1.1.2.6.jar
drippyloadingscreen_1.2.0_MC_1.16.2-1.16.5.jar
DynamicTrees-1.16.5-0.10.0-Beta25.jar
DynamicTreesPlus-1.16.5-0.1.0-Beta10.jar
entityculling-1.3.0.jar
fastbenchminusreplacement-1.4.jar
fastfurnaceminusreplacement-1.1-1.16.3.jar
FastSuite-1.16.4-1.1.1.jar
ferritecore-2.1.0-forge.jar
flywheel-1.16-0.2.4.jar
GameMenuModOption-1.16.4-1.8.jar
getittogetherdrops-1.16.4-v1.1.jar
ironchest-1.16.5-11.2.13.jar
Jade-1.16.4-2.8.0.jar
jei-1.16.5-7.7.1.126.jar
jeiintegration_1.16.5-7.0.1.15.jar
JEITweaker-1.16.5-1.0.1.35.jar
journeymap-1.16.5-5.7.3.jar
JustEnoughResources-1.16.5-0.12.1.128.jar
konkrete_1.3.0_MC_1.16.2-1.16.5.jar
lazydfu-0.1.3.jar
logprot-1.16-1.4.jar
mcjtylib-1.16-5.0.23.jar
Mekanism-1.16.5-10.0.21.448.jar
MouseTweaks-2.14-mc1.16.2.jar
out_of_sight-1.16.4-1.0.1.jar
performant-1.16.2-5-3.72m.jar.disabled
Placebo-1.16.5-4.6.0.jar
Quark-r2.4-317.jar
randompatches-2.4.4-forge.jar
ReAuth-1.16-Forge-3.9.3.jar
rftoolsbase-1.16-2.0.11.jar
smoothboot-forge-1.16.4-1.2.2.jar
sodium-forge-2.9.10+rev.ea6353c.jar
SpawnerFix-1.16.2-1.0.0.2.jar
starlight-forge-1.0.0-RC2-1.16.5.jar
StorageDrawers-1.16.3-8.3.0.jar
xnet-1.16-3.0.13.jar
XNetGases-1.16.5-2.3.7.jar
YungsApi-1.16.4-Forge-12.jar

System Information

• Java Version: 1.8.0_242
• CPU: old and dusty Athlon II x4 640
• GPU: Radeon R9 290X
• Sodium Reforged Version: sodium-forge-2.9.10+rev.ea6353c