Hello battlefield one

Solution
How much system ram do you have? What kind of power supply do you have? Is performance in anything else bad or just this game? Have you tested your system with something else?
Are you playing at 1080p and with the 'ultra' preset? What is your CPU?

Assuming you have a CPU capable of avoiding such frame drops...

...8GB will cause you lower 'minimum' fps manifesting as a 'lag' and one reason why 16GB is the recommended amount for BF1.

In the video below a comparison was made of 8GB vs. 16GB. If you have only 1 x 8GB stick of RAM, then you are running in single channel mode which makes it a little worse. I think that was the case in the video as well.

It is only the minimum fps of 'low' and 'medium' presets that were affected in this instance - because it was tested with a GTX 960. At 'ultra' the system will have been GPU bound anyway.

So... maybe if you run BF1 on the 'low' or 'medium' preset with just 8GB of RAM (at 1080p) you should get a better experience with less lagging, but (assuming your CPU is not the issue here) the best way to solve the lag problem is probably by upgrading to the recommended spec. of 16GB RAM.

https://youtu.be/ped0uNAKXBE?t=391