If your renders are crawling and Task Manager shows your CPU pinned while the graphics card sits idle, Blender is not using your GPU for rendering, and the fix lives in two settings most people miss. You have to enable the GPU in Blender's preferences first, then tell the actual scene to use it. Doing only one of the two leaves you stuck on CPU rendering.

Quick Answer

To fix Blender not using your GPU, open Edit > Preferences > System and select CUDA or OptiX under Cycles Render Devices, ticking your graphics card. Then open Render Properties for your scene and set the device to GPU Compute. Both steps are required: the first enables the card, the second points the render at it.

Step one: enable the GPU in Preferences

This is the setting Blender forgets if you skip it.

  1. Open Edit > Preferences.
  2. Go to the System tab.
  3. Find Cycles Render Devices.
  4. Choose the backend that matches your card. For NVIDIA cards, OptiX is the modern, faster option on supported GPUs, while CUDA is the broadly compatible fallback.
  5. Tick the checkbox next to your graphics card so Blender is allowed to use it.

If no card appears here, that points to a driver issue rather than a Blender setting, so update your GPU drivers and reopen Blender.

Step two: switch the scene to GPU Compute

Enabling the card in Preferences only makes it available. The scene still has to be told to use it.

Open Render Properties (the camera icon in the Properties panel), confirm the render engine is set to Cycles, and change the Device setting from CPU to GPU Compute. This is the step that most often gets missed: people enable the card in Preferences, never touch the scene's device, and wonder why nothing changed. Both halves have to be set.

Why CUDA or OptiX, and why drivers matter

CUDA and OptiX are NVIDIA's two paths into the card for Cycles. OptiX is the newer route and is generally faster on cards that support it, so pick OptiX first and fall back to CUDA if you hit problems. Either way, the card only shows up when your GPU drivers are current. If the System tab lists no device at all, stale or missing drivers are the usual cause, so update them and restart Blender before changing anything else. For heavy rendering and viewport work, a card with more VRAM and CUDA cores makes a real difference, and the workstation graphics card range at Evetech covers the GPUs built for that kind of load. If you are after a complete system rather than just a GPU upgrade, the PC best sellers at Evetech include builds suited to 3D and rendering work.

Frequently Asked Questions

Why is Blender rendering on my CPU instead of my GPU?

Almost always because one of two settings is missing: the GPU is not ticked under Cycles Render Devices in Preferences, or the scene's render device is still set to CPU instead of GPU Compute. Set both and it switches over.

Should I use CUDA or OptiX in Blender?

On a supported NVIDIA card, OptiX is the faster, more modern choice. CUDA is the broadly compatible fallback if OptiX gives you trouble, so try OptiX first.

My GPU does not appear under Cycles Render Devices. What now?

That usually means a driver problem rather than a Blender setting. Update your graphics drivers, restart Blender, and the card should appear in the System tab.

Do I need to change anything per scene?

Yes. Even after enabling the GPU in Preferences, each scene's Render Properties device must be set to GPU Compute, since that setting lives with the scene rather than the application.

Does GPU rendering work with engines other than Cycles?

This CUDA and OptiX device path is specific to Cycles. Make sure your render engine is set to Cycles in Render Properties before expecting the GPU Compute option to apply.

If your renders are still slow once the settings are right, the card itself may be the limit. Explore the workstation graphics card range at Evetech to find a GPU with the VRAM and CUDA cores to push Cycles renders faster.