I wanted to share the process I used to fix the lag spikes and sudden frame drops I was having in World at War (this works identically on Black Ops 1), especially when looking at objects/scenery from a distance. Hopefully this helps anyone dealing with the same issue.

The problem:

Both games run on the DirectX 9 engine, which struggles on modern hardware when handling draw calls with a lot of geometry visible at long range. The result is that FPS stays stable when looking at the ground or in "empty" areas, but drops suddenly the moment you look toward an area with more distant detail/objects.

The fix: DXVK

DXVK is an open-source layer (available on GitHub, project doitsujin/dxvk) that translates DirectX 9 calls into Vulkan. Essentially the game still "thinks" it's running in DX9, but under the hood rendering goes through Vulkan, which handles draw calls far more efficiently and in parallel. The improvement in lag spikes is very noticeable.

Steps:

Download the latest stable DXVK release from the official GitHub repo.
Take the d3d9.dll file from the folder matching your game's architecture (x32/x86 for WaW/BO1) and copy it into the game's installation folder(NOT THE LAUNCHER FOLDER).
Create a text file named dxvk.conf in the same folder, containing this line:
dxvk.enableAsync = True

This step is essential: without async compilation, DXVK causes half-second stutters/freezes every time it encounters a new shader combination that needs to be compiled on the fly. With enableAsync on, compilation happens on a separate thread and the stuttering almost completely disappears.
4. Launch the game: if everything's set up correctly, a .dxvk-cache file should be generated in the game folder, which saves already-compiled pipelines and further reduces stuttering the more you play.

️ Important limitation: only works WITHOUT anticheat active

Here's the part a lot of you will not know: Plutonium's anticheat automatically removes/blocks any third-party DLL injected into the game process, DXVK included, because the injection mechanism is the same one a cheat would use — the anticheat can't tell the two apart, so it blocks both by default. This means:

In LAN mode / private matches hosted by you (where anticheat isn't active): the fix works perfectly, the file is left untouched.
On public servers / official matchmaking (where anticheat is required to connect): the file gets automatically removed and the game falls back to the native DX9 renderer.

So this guide is meant for people playing privately with friends or just wanting a better experience in singleplayer/LAN, not for public online play.

A message to the Plutonium developers:

I really think this is something the dev team should look into and officially support. This isn't a minor edge case — DX9 draw-call performance on distant geometry is a real, reproducible issue affecting both WaW and BO1, and DXVK is a purely cosmetic/performance tool with zero competitive advantage: it doesn't change hitboxes, doesn't reveal information, doesn't affect gameplay logic in any way, it just changes how frames get rendered. Right now the only way to benefit from it is to give up online play entirely, which shouldn't have to be the trade-off. An official whitelist for a verified/signed DXVK build, or native Vulkan support baked into the client, would fix a real performance problem for a lot of players without opening any door for cheating. I'd genuinely encourage the devs to consider this for a future update — I think a lot of the community would benefit, not just me.

I hope you found this guide useful.
I’m neither a programmer nor an expert; I spent four days trying to fix this issue—experimenting with console commands, PC optimization, CPU and GPU overclocking and undervolting, and even a full system restore.

Cheers.