Yeah, the problem is that the game has too much to calculate every frame if you have a large factory, and good gpu doesn't help with that. The solution is for me to have programmed it better, but apart from that, a solution that you can try is to minimize items on belts in the world. You can use long funnels, hovering hands, and rockets for long distance item transport instead of belts.
If it still lags, then you can reduce the number of crafters with items in their inventories. Different crafters also take different lengths of time to process if they have items in their inventory. The time depends on the number of recipes they can perform, with the assembler having the most recipes and the barrel having the fewest.
Usually minimizing items on belts does the trick tho. I hope this helps.