Having some lag how do i fix it?

Hey guys i am making a game call chaser and i have been having this lagging problem where every time i package the game is starts to lag. it usually run smoothly after i put a lot of separated assets. i am not sure what is causing it to lag so bad

Try package game again but this time on low or normal graphic settings in editor.
Switch render to Dx10 if you have installed packaging for Linux.
Check in task bar if your game is a first and last thing that running on Windows.
But anyway we need know your pc spec.

intel i7-9750 CPU 2.60 Ghz
Ram 8g
Graphic card Nvidia Geforce GTX 1650
Windows 10 64bits

i will try to re-package with the lower quality i dont use linux but i am going to check if the render is on Dx 10

also i have the file save in my external hard drive i not sure if that could also be the problem

i was able to to change the render settings and the scalability and the material to low and it runs fine untill i go to the corridor where i have to jump around could it be that put too much stuff?

There are profiling tools that let you figure out where the time is going. I suggest you read up on that section of the documentation!

If you have a corridor, you may be able to significantly improve frame rates by placing pre-computed visibility volumes within the corridor, assuming the walls in the corridor adequately block visibility of other objects, and assuming that the thing causing low frame rate is rendering related.

Note that performance management is a HUGE topic. There are no automatic solutions that “just work” for everyone. Making high performance games is a craft, that requires dedication and hard work, and some of that work is just learning what all the tools are, what they mean, and how to appropriately use them.

thanks but i have to confess i am still new to the whole UE4 talk
can you explain in more detail please?