What does OpenCL do and how do I use it in Capture One?
Optimal speed through OpenCL/GPU
OpenCL is short for Open Compute Language - an open standard defining how to interface and utilize many processing cores with graphics cards (GPU), multiprocessor CPUs and RAM. Four major companies have developed drivers for OpenCL: NVidia, AMD, Intel, Apple. For Mac OS X these drivers are part of the operating system, while those have to be installed manually when working on Windows. The driver itself performs the runtime compilation dedicated to the graphics card in the machine at hand. Only relatively new GPU cards have enough compute power to be utilized effectively.
Open CL will dedicate memory to several actions in Capture One:
• Preview Update with different settings, styles, etc.: RAM
• Sorting/Rating: CPU cores and SSD speed
• Fit Image to Screen: GPU cores
• Process time: GPU processing units and CPU's and RAM
How to enable Open CL and what to expect from it
In Capture One 10 and later versions, the Hardware Acceleration option is set to Auto by default. In Capture One 9.3 and earlier versions, the Hardware Acceleration option is disabled by default so that you have to turn the preferences to Auto to start testing your hardware for compatibility. You can expect much faster file processing and the overall performance improvement with the suggested hardware.
Windows driver requirements
• For AMD/ATI graphics: AMD Stream 2.2, Catalyst 12.10 or later versions, download here and choose AMD Catalyst™ Accelerated Parallel Processing (APP) Technology Edition.
• For Nvidia graphics: NVidia Display driver 306.97 or later version. Download here.
In case there are issues when using OpenCL
- In the System Preferences -> Energy Saver, disable Automatic Graphics Switching.
- Clear the ImageCore cache by deleting the folder (then restart Capture One). For macOS users, navigate to Hard Drive -> Users -> Shared -> Capture One -> ImageCore (version 12.1.5 and earlier) or Library -> Application Support -> Capture One -> ImageCore (version 20.0.0 and later) and delete it. For Windows users, go to C:\Users\User_Name\AppData\Local\CaptureOne\ImageCore (version 20.0.0 and later) or C:\Users\ProgramData\PhaseOne\CaptureOne\ImageCore (version 12.1.5 and earlier).
- If problems still occur, navigate to the Preferences -> General -> Hardware Acceleration (Use OpenCL for) and set the Display and Processing options to Never.
Disable OpenCL in Capture One in case of a crash at startup
• Windows: Run the script DONOT_useopencl.reg and restart Capture One (the download also contains a restore script to re-enable OpenCL useopencl.reg) Download here.
• MacOS: Download AdjustOpenCL_External.zip and run this application AdjustOpenCL_External.app, disable OpenCL, and restart Capture One.
OpenCL hardware support for Capture One
In general, any GPU that supports OpenCL 1.2 or later versions and has a minimum of 1GB of dedicated RAM will be utilized. However, we recommend having at least 2GB of RAM for intensive processes such as working with large files and using local adjustments. When it comes to high-DPI display such as 4/5K iMacs or any other high-resolution displays, we recommend having a minimum of 4GB of dedicated RAM.
Which Graphics Card (GPU) should I buy?
We often get asked which graphics card makes Capture One perform at its fastest. Obviously, newer and faster cards are constantly being released, so it's difficult to recommend a certain brand associated with GPUs. When you are going to get a GPU, we recommend paying attention to such characteristics as the number of Stream Processors (AMD) and the number of CUDA Cores (Nvidia). The higher the value, the more processors are available, giving you a faster experience in Capture One.
How many GPUs can I use with Capture One?
Capture One supports up to 4 GPUs, but make sure that all the GPUs you use are produced by the same manufacturer ( i.e. AMD or Nvidia).