CPU vs GPU bottleneck, explained (and which settings matter for each)

Updated November 2026 · 6 min read

Short answer

If your GPU sits near 95-99% usage, you're GPU-limited: lower shadows, effects, anti-aliasing and resolution. If GPU usage is well below that and FPS doesn't rise when you lower resolution, you're CPU-limited: lower view distance, simulation and crowd settings instead.

To make a frame, the CPU first works out what's happening (physics, AI, what's visible) and hands a list of drawing work to the GPU, which then draws it. Whichever side takes longer sets your frame rate. The other side waits.

Why it matters

Lowering a GPU-heavy setting only helps if the GPU is the one holding you back. If you're CPU-limited, turning shadows from Ultra to Low can change almost nothing, because the GPU was already waiting. That's the most common reason "I lowered everything and nothing changed".

How to tell which one you are

Watch GPU usage. In Task Manager's Performance tab, or an overlay like the one in your GPU driver. Consistently 95-99% while playing means GPU-limited. Clearly lower (say 50-75%) usually means the CPU is the limit, or a frame cap is.
The resolution test. Drop the game's resolution or render scale a lot. If FPS jumps, you were GPU-limited. If it barely moves, you're CPU-limited.
Check for a cap. If FPS sits exactly at 60, 120 or 144 and the GPU isn't busy, a frame limit or V-Sync is holding you, not your hardware.

Measuring tools like PresentMon report "GPU busy" time for every frame, which is the most precise version of this: if the GPU is busy for only 58% of each frame, the CPU (or a cap) is setting the pace. Framecalm uses exactly this.

Settings that help when you're GPU-limited

Shadows, global illumination, reflections, volumetric fog
Anti-aliasing and post-processing
Resolution / render scale, or upscalers like DLSS, FSR and XeSS

Settings that help when you're CPU-limited

View distance, render distance, simulation distance
Crowd, NPC and physics detail
In some games, turning on multithreaded rendering
Closing heavy background apps (browsers with many tabs, launchers, RGB software)

It can change mid-game

A busy city or a 50-player fight can be CPU-limited while an empty field is GPU-limited. That's why measuring a repeatable, typical scene beats looking at a single number.