If you only change two graphics settings to improve your frame rate, make them shadows and ambient occlusion. Both simulate realistic lighting behaviour, and both are disproportionately expensive to compute compared with how much they actually add to your enjoyment of a game while you're playing rather than admiring a screenshot.

Key takeaway: Shadows and ambient occlusion are two of the most GPU-intensive settings in any modern game relative to their visual impact during actual gameplay, making them the best first targets on a budget PC.

How shadows are rendered, and why they're expensive

To draw realistic shadows, a game has to render a "shadow map" — essentially a second view of the scene from the perspective of each light source, used to work out what's blocked from that light and therefore in shadow. Higher shadow quality settings increase the resolution of this shadow map and the distance at which shadows are drawn, both of which add real GPU workload. Dynamic shadows that update as objects and lights move are considerably more expensive than static, baked shadows.

Because most players are focused on gameplay rather than examining the edges of shadows, dropping shadow quality from Ultra or High to Medium or even Low is one of the least noticeable changes you can make, yet it often returns a very real chunk of frame rate on older graphics cards.

What ambient occlusion actually adds

Ambient occlusion (AO) softens lighting in areas where objects meet or crevices form — the corner where a wall meets the floor, or under a chair. Common implementations include SSAO (Screen Space Ambient Occlusion) and the more advanced HBAO (Horizon-Based Ambient Occlusion). It adds subtle depth and realism to a scene, but it is a per-pixel calculation performed on top of everything already on screen, making it surprisingly costly for what is, in practice, a fairly minor visual improvement during fast gameplay.

  1. Open your game's video settings and find "Shadow Quality" or "Shadows."
  2. Drop it two levels (for example, from Ultra to Medium) and note the FPS change using your game's built-in counter or an overlay tool.
  3. Find "Ambient Occlusion" or "AO" and either disable it entirely or switch from HBAO to the lighter SSAO option if both are offered.
  4. If the game offers separate "Shadow Distance" and "Shadow Resolution" sliders, reduce shadow distance first, since distant shadows are rarely noticed.
  5. Re-test your frame rate; you should typically see a noticeable improvement with only a subtle visual difference.

Tip: If a game lets you disable dynamic shadows for smaller objects (like grass or foliage) while keeping shadows on for characters and buildings, that partial setting often gives most of the performance benefit while keeping the scene looking grounded.

Before you start: A small number of games use ambient occlusion or contact shadows as part of their core lighting model rather than a pure add-on effect, so test the change in a real gameplay scene rather than a menu screenshot before committing to it.

Frequently asked questions

Will turning off shadows make the game look flat?
Turning shadows off entirely can look flat, but lowering shadow quality or distance rather than disabling them completely usually preserves most of the visual depth while still boosting FPS.
What's the difference between SSAO and HBAO?
HBAO is a more accurate, more expensive form of ambient occlusion than the older SSAO technique. On a budget GPU, choosing SSAO over HBAO (or disabling AO entirely) is an easy way to save performance.
Do shadows affect VRAM usage as well as GPU load?
Yes, higher-resolution shadow maps also consume video memory, so on GPUs with limited VRAM, lowering shadow quality can help avoid stuttering caused by running out of memory too.

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