Where is KFEngine.ini?

In C:\Users\ \Documents\My Games\KillingFloor2\KFGame\Config.

What value should ImageReflectionTextureSize have?

The default is 1024. The author suggests testing 512 first, then smaller values (256, 128 and so on) if you want.

KF2 Performance Tweak: ImageReflectionTextureSize and -dx 10

A very short community tip for squeezing more performance out of Killing Floor 2 on weaker systems. See also the config optimization guide and render distance, gore and audio tweaks for broader ini changes.

Edit KFEngine.ini

Go to C:\Users\[Your User]\Documents\My Games\KillingFloor2\KFGame\Config and open KFEngine.ini with a text editor.

KFEngine.ini in the Config folder

Open KFEngine.ini in a text editor.

Find the line ImageReflectionTextureSize=1024 and change 1024 to a smaller value. The author lists 512, 256, 128, 64, 32, 16, 8, 4, 2 and 1 as possible values, but recommends experimenting with 512 first and only then trying the others.

Launch option

In the Steam library, open Killing Floor 2 Properties and in Launch Options enter:

-dx 10

Steam launch options

The launch options field.

This forces the DirectX 10 renderer. The author hopes this helps you.

Notes

Back up KFEngine.ini before editing so you can restore the default.
Lower reflection texture sizes reduce reflection detail; values near 1 will look noticeably worse, so adjust gradually.

FAQ

Where is KFEngine.ini?: In C:\Users\<your user>\Documents\My Games\KillingFloor2\KFGame\Config.
What value should ImageReflectionTextureSize have?: The default is 1024. The author suggests testing 512 first, then smaller values (256, 128 and so on) if you want.