KF2 FPS Boost on Big Modded Servers: KFEngine.ini Tweaks

This guide collects KFEngine.ini and launch-option tweaks aimed at one problem: low and unstable FPS in late waves on big, heavily modded Killing Floor 2 servers. The author reports going from roughly 40 to roughly 75 FPS on large waves with an 8 GB GTX 1080. Results depend on your CPU, VRAM, RAM and server load, so test changes one at a time. All edits are for Ultra graphics; on a weak PC, lowering in-game settings is the better route. See also advanced FPS config for the original game.

All files are in Documents\My Games\KillingFloor2\KFGame\Config\. Back them up first.

Step 1: texture cache (PoolSize)

In KFEngine.ini, section [TextureStreaming], change PoolSize (default range 160 to 2000) to fit your VRAM in megabytes:

VRAM	PoolSize
2 GB	1000
4 GB	2000
6 GB	3000
8 GB	4000
10 GB	5000 (6000 is the maximum)

If you get stutter, the value is too high: lower it.

PoolSize under [TextureStreaming].

Step 2: streaming pool

In [SystemSettings] add r.Streaming.PoolSize=4000 (4000 suits 8 GB; scale to your card). This makes the engine keep more streamed textures in memory.

The streaming pool line in [SystemSettings].

Steps 1 and 2 are the most important; usually they alone give most of the gain.

Step 3: disable streaming limits

Add these lines to [SystemSettings] so used textures stay in memory, reducing pop-in and freezes:

r.Streaming.FullyLoadUsedTextures=1
r.Streaming.HLODStrategy=2
r.Streaming.UseFixedPoolSize=1

Streaming limit settings.

Step 4: advanced options

Only for cards with 6 GB VRAM or more. In [TextureStreaming]:

MemoryMargin=128
MemoryLoss=0
HysteresisLimit=40
DropMipLevelsLimit=16
StopIncreasingLimit=12
UsePriorityStreaming=True
UseTextureFileCache=True

Priority streaming smooths loading and avoids memory spikes with a large pool, especially on an HDD. The texture file cache matters on an HDD and gives only a small boost on an SSD.

The [TextureStreaming] block.

In [SystemSettings] you can also add r.OneFrameThreadLag=0 and r.Streaming.DefragDynamicBounds=1 (some may be ignored by your build, which is harmless).

To avoid shadow micro-stutter, create a [MemoryPools] section if missing and set both values to match your PC:

FLightPrimitiveInteractionInitialBlockSize=2048
FModShadowRenderPrimitiveInteractionInitialBlockSize=2048

The default is 512. Suggested values: 1024 for a low PC (8 GB RAM, GTX 960 or weaker), 2048 for mid (16 GB, GTX 1060-1070), 4096 for high (32 GB, GTX 1080 / RTX 3060 and up), 8192 for extreme and mostly pointless.

Step 5: Steam launch options

Right-click Killing Floor 2 in Steam, open Properties and add to Launch Options:

-USEALLAVAILABLECORES -PREFERPROCESSOR=1

Launch options field in the game properties.

CPU and physics tweaks

These improve thread handling and reduce PhysX micro-lag without changing graphics.

• [SystemSettings]: r.OneFrameThreadLag=0, r.FinishCurrentFrame=0, r.Streaming.NumStaticComponentsProcessedPerFrame=500, r.Streaming.NumDynamicComponentsProcessedPerFrame=200. Removes the one-frame CPU/GPU lag and loads weapons and effects faster.
• [Core.System]: bUseBackgroundLevelStreaming=False, bDisableLogging=True. Cuts background loading work, which is unnecessary on SSDs.
• [Engine.Physics]: bPhysicsAsyncScene=True, bEnableAsyncScene=True, PhysXGpuHeapSize=128, PhysXMeshCacheSize=32. Asynchronous physics offloads the main thread.
• [Engine.Engine]: bSmoothFrameRate=True, MinSmoothedFrameRate=60, MaxSmoothedFrameRate=120, bUseVSync=False, bUseThreadedRendering=True, bUseThreadedUpdate=True.
• [MemoryPools]: FParticleRenderDataPoolSize=1024, FPrimitiveSceneProxyPoolSize=2048. Fewer reallocations during big blood-heavy waves.

Crash prevention

For long sessions (2+ hours), heavy mod maps and many mods, set these [Core.System] values to 0:

MaxObjectsNotConsideredByGC=0
SizeOfPermanentObjectPool=0
StaleCacheDays=0
MaxStaleCacheSize=0
MaxOverallCacheSize=0
PackageSizeSoftLimit=0

They stop obsolete objects and caches from accumulating, which reduces memory-saturation crashes and freezes on modded multiplayer.

Core.System memory settings set to zero.

Extra tips

• Disable logging with bDisableLogging=True under [Core.Log] for a small gain.
• Audio: under [Audio] set MaxChannels=64, UseEffectsProcessing=True, Use3DSound=True, TimeBetweenHWUpdates=15, bUseThreadedAudio=True.
• Async preloading: under [Engine.Streaming] set s.MinBulkDataSizeForAsyncLoading=0 and s.AsyncLoadingThreadEnabled=True, so assets load in the background.

The author's profile and results

Setup: i7-5820K, GTX 1080 8 GB, 32 GB RAM, Ultra graphics, gore on, NVIDIA Flex off. Key values: r.Streaming.PoolSize=3500 and PoolSize=3500, r.Streaming.UseFixedPoolSize=0, PhysX heap 256 and mesh cache 64, r.ShadowQuality=3, r.MotionBlurQuality=0, r.MaxAnisotropy=8, memory-pool blocks 2048, and the Core.System zeroes above with logging left on for crash diagnostics. Reported FPS on an ultra-modded server:

Waves	Min/Max	Average
0-25	40/60	55
26-30	30/60	45
31-35	25/50	30

FAQ

• The game will not start after edits. Delete the modified ini files; they are regenerated with defaults.
• FPS did not improve. Test one change at a time and do not set the pool above what your VRAM allows (for 4 GB stay under about 2000-2500).
• How to check? Use F3 in-game or the Steam FPS overlay.
• Restore defaults. Delete KFEngine.ini, KFSystemSettings.ini and KFGame.ini in the Config folder.
• Modded servers and custom maps. The tweaks help most on servers with many Zeds and heavy effects.