Make the Fusion Page Faster
Welcome to a deep dive into optimizing your workflow in DaVinci Resolve 21! This covers the best undocumented tricks and settings to make the Fusion page run significantly faster.
Whether you are dealing with heavy node trees or massive image resolutions, these tips will help you reclaim your real-time playback.
Downscale to Timeline Resolution
Most of the time, the footage we work with is much larger than our actual delivery timeline.
You can automatically downscale your media in the Fusion page to match your timeline resolution by hitting Shift-9 to open Project Settings.
Navigate to the Fusion tab and check "Down Scale to Timeline Resolution for Timeline Clip Compositions".
This automatically resizes your media (for example, shrinking 4K footage to fit a 1080p timeline), leading to faster renders and processing.
Keep in mind that this setting does not work with EXR sequences, likely due to how different embedded render passes are handled.
Optimize Photo Album Previews
Working with massive, 60-megapixel photos can easily bog down your computer.
In DaVinci Resolve 21, the new photo album page automatically downscales these massive images for preview purposes without affecting the final render.
To speed things up even further in Fusion, go to your Playback menu and adjust the "Photo Album Preview Resolution" to a setting like "Quarter".
This will drastically reduce the pixel count Fusion has to calculate while you work.
Force Float 16 or 32 Playback via Performance Mode
DaVinci Resolve processes its final renders in high-precision 32-bit float, but by default, it uses 16-bit float for playback in Fusion.
Sometimes, highly specific math like stenciling, blurring, and in-painting requires 32-bit float to preview accurately.
To force this, go to DaVinci Resolve > Preferences > User > Playback Settings.
Under "Performance Mode," change the setting from "Automatic" to "Disable" (or choose "Manual" and adjust image processing).
This ensures your playback identically matches your final output precision.
Turn Off Viewer Motion Blur
Motion blur looks great, but calculating where pixels came from and where they are going takes a heavy toll on performance.
You can disable motion blur exclusively for your preview window.
Simply right-click anywhere on the viewer's transport/play bar, navigate to "Motion Blur," and deselect the checkbox.
Your workspace will run faster, but your final exported video will still retain the beautiful motion blur you set up in your Merge or Transform nodes.
Pre-Render with Saver and Loader Nodes
If you've built a complex composition and are happy with it, "bake" it so Fusion doesn't have to recalculate it every time you hit play.
Add a Saver node (Shift + Space, type "Saver").
Under the Format tab, set the output to EXR.
Set the compression type to DWA 256 (DWAB), leave compression at 45, and choose Float 16.
This creates a high-quality, lightweight file (around 2MB per frame at 1080p) similar to ProRes 4444.
Name your file (e.g., rendername..exr to keep the frame numbers separated) and go to Fusion > Render All Savers.
Once baked, bring the sequence back in using a Loader node for buttery smooth, real-time playback.
Map and Manage Your Disk Cache
You can bypass the Saver/Loader method by right-clicking a node and selecting Cache to Disk > Pre-Render.
This creates temporary raw files that are 32-bit float and uncompressed, meaning they are incredibly large (often 30+ megabytes per frame).
Because these fill up internal drives fast, map your cache to a dedicated, fast external NVMe SSD.
You can set this default path by going to Fusion > Fusion Settings > Path Mapping > Disk Caches.
To delete the cache, right-click the cached node and select Cache to Disk > Delete Cache.
The Crop and Uncrop Trick
Don't waste processing power calculating pixels you aren't touching!
Use a Crop node to isolate just the area of the screen you are painting or cloning.
Do all your heavy node work on this tiny, cropped resolution.
To put it back seamlessly, copy and paste the Crop node, type the original project resolution back into the X/Y sizes, and turn the X/Y offsets into negative numbers.
Bonus Tip: You can download a macro called "Crop in a Half" by Second Band from the Steak Underwater (We Suck Less) Fusion forums. It features an "Export Inverted Crop" button that does the reverse math for you instantly!
Limit the Domain of Definition (DoD)
The Domain of Definition is the literal bounding box of pixels that Fusion calculates.
You can view this boundary by clicking the three-dot options menu in the viewer, navigating to Region, and selecting Show DoD.
Use a Set Domain node to manually drag bounding lines around the area you want to work on, effectively cutting away the rest of the image from the math equation.
Beware: adding a Paint node after this will expand the DoD back to the full frame.
To fix this, add an Auto Domain node after your paintwork to shrink the bounding box back down.
For ultimate optimization, use a Difference Key to restrict the calculation exclusively to the actual pixels you painted.
Disable Node Updates
By default, Fusion updates every node on every single frame.
If you are using a Time Speed node to create a freeze-frame (by clicking the freeze frame button), it doesn't need to update endlessly.
Right-click the node, go to Modes, and uncheck Update.
This also works wonders for Paint nodes. Once you've painted your static stroke, disabling the update will force it to only load the cache once, significantly speeding up playback when using Frame Holds.
Master Your Cache
When doing heavy paintwork with dozens of clone strokes, Fusion can start to feel buggy or slow.
To quickly clear your paint node cache, temporarily switch your tool from "Stroke" to "Select." This flushes the brush's memory, allowing you to switch back and paint freshly on top of your previous work.
To clear the entire system cache, look at the RAM usage indicator in the bottom right corner of the UI.
Right-click the numbers and select Purge Cache to wipe the green RAM line and force a clean recalculation.
Enable Viewer Proxies
Unlike edit page proxies (which read entirely different media files), Fusion proxies simply lower the display resolution of your viewer.
Right-click the transport bar and select Proxy.
Next, change your Timeline Playback Resolution to Half or Quarter.
Your underlying math stays at full UHD resolution, but the viewer displays fewer pixels, making animation previews much faster.
Bonus Tip: To see your exact pixels clearly when zoomed in, open the three-dot menu in the viewer and turn off Smooth Resize, which disables the automatic blurring effect. You can save this by right-clicking the viewer and selecting Settings > Save Defaults.
