# Multi-GPU systems Locate and work with internal and external GPUs and their displays, video memory, and performance tradeoffs. ## Discussion Your app can submit work to any or all of the GPUs of a system that supports multiple GPUs. For example, every Mac notebook, such as a MacBook Pro, has an internal GPU, but some have two.  A Mac may have a Thunderbolt connection to an external GPU and its displays.  Some systems may have even more complicated arrangements of internal and multiple external GPUs and displays.  For more information about Mac configurations with GPUs and displays, see [Assessing multi-GPU and multidisplay setups on an Intel-based Mac](/documentation/Metal/assessing-multi-gpu-and-multi-display-setups-on-an-intel-based-mac). Start by locating all GPUs in a system and identifying their types (see [Finding multiple GPUs on an Intel-based Mac](/documentation/Metal/finding-multiple-gpus-on-an-intel-based-mac)). Alternatively, you can locate a specific GPU that’s driving a display (see [Getting the GPU that drives a view’s display](/documentation/Metal/getting-the-gpu-that-drives-a-views-display)). When selecting a GPU, consider its memory bandwidth and the storage mode options for its memory resources (see [Adjusting for GPU memory bandwidth tradeoffs](/documentation/Metal/adjusting-for-gpu-memory-bandwidth-tradeoffs)). For examples of how to use external GPUs in your graphics rendering or compute processing workflows, see the following: - [Selecting device objects for graphics rendering](/documentation/Metal/selecting-device-objects-for-graphics-rendering) - [Selecting device objects for compute processing](/documentation/Metal/selecting-device-objects-for-compute-processing) For more information about external GPU configurations, see [Use an external graphics processor with your Mac](https://support.apple.com/kb/HT208544). > Note: > The system may gain or lose an external GPU at any time (see ). ## Topics ### Locating GPUs [Finding multiple GPUs on an Intel-based Mac](/documentation/Metal/finding-multiple-gpus-on-an-intel-based-mac) Locate, identify, and choose suitable GPUs for your app. [Getting the GPU that drives a view’s display](/documentation/Metal/getting-the-gpu-that-drives-a-views-display) Keep up to date with the optimal device for your display. [`MTLCopyAllDevices()`](/documentation/Metal/MTLCopyAllDevices()) Returns an array of all the Metal device instances in the system. [`MTLCopyAllDevicesWithObserver(handler:)`](/documentation/Metal/MTLCopyAllDevicesWithObserver(handler:)) Returns an array of all the Metal GPU devices in the system and registers a notification handler that Metal calls when the device list changes. [`MTLCopyAllDevicesWithObserver`](/documentation/Metal/MTLCopyAllDevicesWithObserver) Returns an array of all the Metal GPU devices in the system and registers a notification handler that Metal calls when the device list changes. [`MTLRemoveDeviceObserver(_:)`](/documentation/Metal/MTLRemoveDeviceObserver(_:)) Removes a registered observer of device notifications. [`MTLDeviceNotificationHandler`](/documentation/Metal/MTLDeviceNotificationHandler) A Swift closure or an Objective-C block that Metal calls when the system adds or removes a GPU device. [`MTLDeviceNotificationName`](/documentation/Metal/MTLDeviceNotificationName) A notification that represents a change to a GPU device in the system. ### Selecting GPUs [Adjusting for GPU memory bandwidth tradeoffs](/documentation/Metal/adjusting-for-gpu-memory-bandwidth-tradeoffs) Choose a suitable GPU and memory storage mode for tasks based on that GPU’s memory bandwidth on a Mac. [Assessing multi-GPU and multidisplay setups on an Intel-based Mac](/documentation/Metal/assessing-multi-gpu-and-multi-display-setups-on-an-intel-based-mac) Learn the possible GPU and display configurations for a Mac and their limitations. [Selecting device objects for graphics rendering](/documentation/Metal/selecting-device-objects-for-graphics-rendering) Switch dynamically between multiple GPUs to efficiently render to a display. [Selecting device objects for compute processing](/documentation/Metal/selecting-device-objects-for-compute-processing) Switch dynamically between multiple GPUs to efficiently execute a compute-intensive simulation. ### Working with external GPUs [Handling external GPU additions and removals](/documentation/Metal/handling-external-gpu-additions-and-removals) Register and respond to external GPU notifications that a person initiates. [Transferring data between connected GPUs](/documentation/Metal/transferring-data-between-connected-gpus) Use high-speed connections between GPUs to transfer data quickly. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)