KF2 Low FPS Fix: Force DirectX 10 With the -dx10 Option
Killing Floor 2 can run noticeably slower than it should on mid-range and older hardware. One of the simplest fixes needs no config editing at all: a single Steam launch option.
Who this works for
The trick only makes sense if your video card supports DirectX 11 or newer. Those are the cards where the game picks DirectX 11 on its own and can lose a lot of frame rate because of it.
What to do
- Open your Steam library and right-click Killing Floor 2.
- Choose Properties, then General.
- In the Launch Options field type
-dx10(without quotes). - Start the game.
Why it works
KF2 automatically launches in DirectX 11 whenever the GPU supports it. On some systems this lowers FPS considerably. The -dx10 option makes the game start in DirectX 10 instead, which often gives a much higher or at least a playable frame rate. The renderer cannot be changed from the in-game menus, so the launch option is the only straightforward way to do it.
Going further
If you still need more performance, combine this with the INI tweaks described in KF2 FPS tweaks: texture streaming and dynamic lights and KF2 video settings FPS guide.
FAQ
- How do I force DirectX 10 in Killing Floor 2?
- Open the game's properties in Steam, find Launch Options and enter -dx10 (without quotes). The game will then start in DirectX 10 mode.
- Why does this raise FPS?
- KF2 automatically starts in DirectX 11 when the video card supports it, which can cost a lot of performance. Forcing DirectX 10 avoids that.
- Can I switch DirectX inside the game?
- No. KF2 has no in-game DirectX setting, which is why a launch option is needed.
