theres a thing on this page to disable it curious what is it exactly I looked it up on google not getting a exact answer.
Topic on Talk:Killing Floor 2
From what I have understood, it's technique to load textures from drive when needed and only the quality they are needed, instead of loading everything. If you have ever seen game going from mushy looking to regular when level/model is loaded, that's texture streaming. Really good thing on lower end systems, games with only 32-bit executable as well as consoles and many Unreal 3 games use it.
However the downside is that there can be fps drops especially in high paced action, which is more visible when playing from HDD instead of SSD. Not sure about any other downsides.
I should actually research this more, as having 16 gigs of RAM should give me huge improvements with this.