I'm making an inventory sorting system where I use inventory readers underneath actually additions storage crates and item exporters attached to the back, each containing a variable card that's been linked to the list attribute of their respective inventory reader. However once I start placing the variable cards inside the item exporter, the game starts to lag severely and gets worse the more variable cards I place inside their respective item exporters Here's a picture of the set up to get a better idea:

I've implemented a small optimization that should have a huge impact on item list performance.
Feel free to try out the latest Integrated Dynamics dev build to see if this helps in your case.

@Macrophage001 Can you try profiling your setup and send me the .nps file?

More information can be found here: https://refinedstorage.raoulvdberge.com/wiki/profiling

Here you go:

lag_spike.zip

Thanks!
It looks like the main bottleneck seem to be the usage of list variables, which is understandable.
Will have a look if I can do some optimizations there.

In the meantime, you can reduce server load by reducing the frequency of some of your parts, as I assume you don't need them working every tick.

Note to self: optimize list proxies.

Ah ok. Thanks for the advice!