Just how slow are blueprints?

Officially, it is said that blueprints is ~10x slower than C++. This isn’t really an issue with blueprint. Is an issue with all scripting languages. It is why it is important to have access to the source code besides core extensions.

Anyway, most games won’t be affected by it since generally you don’t bottleneck at the processor, but at the graphics card or memory.

If you are trying to do lots of math in a short period of time, or AI, then those are the kinds of areas that you would be better off in C++. Generally though you won’t notice the difference.