devtrackers.gg
It's entirely bound to the single-threaded CPU performance. However, mods can be poorly optimized or broken in ways that will heavily degrade performance, so it may be a mod or mods causing issues - even mods that seem to do something simple.
A freeze every 2 seconds likely indicates some exception being thrown during periodic processing, related to a mod. Exceptions create huge lag spikes like that. Essentially this is a mod bug and you can investigate by looking at the console log in dev mode.
