The game has hard limit of one recipe completion per tick. Any additional speed modules past this point will have no effect on recipe speed. However, productivity is calculated as if this limit does not exist.
Helmod is showing that 580 Iron plates will make 1.5k Electronic circuits. Production graph is showing that 580 Iron plates is actually making 13k Electronic circuits.
Source: https://mods.factorio.com/mod/helmod/discussion/641733f073baffca14f08091
The game has hard limit of one recipe completion per tick. Any additional speed modules past this point will have no effect on recipe speed. However, productivity is calculated as if this limit does not exist.
Personally, I think this is a base game bug. The Factorio devs have indicated that it will not be fixed so we have to live with it. https://forums.factorio.com/viewtopic.php?f=58&t=72618
Example
Mod list:
Helmod is showing that 580 Iron plates will make 1.5k Electronic circuits. Production graph is showing that 580 Iron plates is actually making 13k Electronic circuits.