This is an addon that applies performance patches to Tom's Simple Storage Mod. It's currently only available for 1.20.1 Forge.

Tom's Storage must still be installed!

On newer versions (including 1.21.1) Tom's has added a few new optimizations of their own - This mod will probably not be ported to those versions, since it's not as necessary. 

Benchmarks

Test set:

Test 1 (Large network, heavy interaction):

Without Performant Storage:

With Performant Storage:

Test 2 (Large network, terminal open):

Without Performant Storage:

With Performant Storage:

Disclaimer: Of course, these tests were performed by hand and not automated or repeated for statistical significance, so they may be inconsistent by a few seconds and there are other minor anomalies. But at around a 90% to 95% increase in performance, I think more accurate statistics are probably unnecessary. Feel free to profile it yourself though!