This may be an FNEI problem, but after installing this mod, FNEI freezes the game for a second every time a recipe loads.

Additionally, the game freezes for half a second whenever a research is finished. I haven't tried it yet, but may be able to prevent this one by disabling research completion notifications.

I reported the problem with FNEI on their GitHub since I don't think it's caused by anything in my mod. Hopefully we can work together to fix it.

Which version of Factorio and this mod are you using? Research completion notifications shouldn't cause any significant lag. Do you also have FNEI open when this happens?

I'm running Factorio 1.1.6. Latest version of improved research queue.

I had to remove it for now as the freezes were unbearable.

Another thing I noticed is that the search bar in the mod doesn't work so i find myself just going to normal research and searching and adding all the research there. then only using IRQ to move research around as priorities change.

Could you upload your save file and link it here so I can investigate?