diff --git a/Diffusion-macOS/ControlsView.swift b/Diffusion-macOS/ControlsView.swift
index 6469bea..dfdaf82 100644
--- a/Diffusion-macOS/ControlsView.swift
+++ b/Diffusion-macOS/ControlsView.swift
@@ -57,7 +57,7 @@ struct ControlsView: View {
     @State private var disclosedSteps = false
     @State private var disclosedSeed = false
     @State private var disclosedAdvanced = false
-    @State private var useANE = false
+    @State private var useANE = (Settings.shared.userSelectedAttentionVariant ?? ModelInfo.defaultAttention) == .splitEinsum
 
     // TODO: refactor download with similar code in Loading.swift (iOS)
     @State private var stateSubscriber: Cancellable?
@@ -66,7 +66,8 @@ struct ControlsView: View {
 
     // TODO: make this computed, and observable, and easy to read
     @State private var mustShowSafetyCheckerDisclaimer = false
-    
+    @State private var mustShowModelDownloadDisclaimer = false      // When changing advanced settings
+
     @State private var showModelsHelp = false
     @State private var showPromptsHelp = false
     @State private var showGuidanceHelp = false
@@ -81,6 +82,11 @@ struct ControlsView: View {
         mustShowSafetyCheckerDisclaimer = generation.disableSafety && !Settings.shared.safetyCheckerDisclaimerShown
     }
     
+    func updateANEState() {
+        Settings.shared.userSelectedAttentionVariant = useANE ? .splitEinsum : .original
+        modelDidChange(model: Settings.shared.currentModel)
+    }
+    
     func modelDidChange(model: ModelInfo) {
         print("Loading model \(model)")
         Settings.shared.currentModel = model
@@ -117,8 +123,8 @@ struct ControlsView: View {
         }
     }
     
-    func isModelDownloaded(_ model: ModelInfo) -> Bool {
-        PipelineLoader(model: model, variant: Settings.shared.userSelectedAttentionVariant).ready
+    func isModelDownloaded(_ model: ModelInfo, variant: AttentionVariant? = nil) -> Bool {
+        PipelineLoader(model: model, variant: variant ?? Settings.shared.userSelectedAttentionVariant).ready
     }
     
     func modelLabel(_ model: ModelInfo) -> Text {
@@ -282,10 +288,23 @@ struct ControlsView: View {
                     DisclosureGroup(isExpanded: $disclosedAdvanced) {
                         HStack {
                             Toggle("Use Neural Engine", isOn: $useANE).onChange(of: useANE) { value in
-                                print(value)
-                            }.padding(.leading, 10)
+                                guard let currentModel = ModelInfo.from(modelVersion: model) else { return }
+                                let variantDownloaded = isModelDownloaded(currentModel, variant: useANE ? .splitEinsum : .original)
+                                if variantDownloaded {
+                                    updateANEState()
+                                } else {
+                                    mustShowModelDownloadDisclaimer.toggle()
+                                }
+                            }
+                            .padding(.leading, 10)
                             Spacer()
                         }
+                        .alert("Download Required", isPresented: $mustShowModelDownloadDisclaimer, actions: {
+                            Button("Cancel", role: .destructive) { useANE.toggle() }
+                            Button("Download", role: .cancel) { updateANEState() }
+                        }, message: {
+                            Text("This setting requires a new version of the selected model.")
+                        })
                     } label: {
                         HStack {
                             Label("Advanced", systemImage: "terminal").foregroundColor(.secondary)
diff --git a/Diffusion/ModelInfo.swift b/Diffusion/ModelInfo.swift
index 9b94c9d..f9865c9 100644
--- a/Diffusion/ModelInfo.swift
+++ b/Diffusion/ModelInfo.swift
@@ -39,10 +39,15 @@ struct ModelInfo {
 }
 
 extension ModelInfo {
-    var bestAttention: AttentionVariant {
+    static var defaultAttention: AttentionVariant {
         return runningOnMac ? .original : .splitEinsum
     }
     
+    // TODO: heuristics per {model, device}
+    var bestAttention: AttentionVariant {
+        return ModelInfo.defaultAttention
+    }
+    
     func modelURL(for variant: AttentionVariant) -> URL {
         // Pattern: https://huggingface.co/pcuenq/coreml-stable-diffusion/resolve/main/coreml-stable-diffusion-v1-5_original_compiled.zip
         let suffix: String
@@ -57,15 +62,7 @@ extension ModelInfo {
     /// Best variant for the current platform.
     /// Currently using `split_einsum` for iOS and `original` for macOS, but could vary depending on model.
     var bestURL: URL { modelURL(for: bestAttention) }
-    
-    /// Best units for current platform.
-    /// Currently using `cpuAndNeuralEngine` for iOS and `cpuAndGPU` for macOS, but could vary depending on model.
-    /// .all works for v1.4, but not for v1.5.
-    // TODO: measure performance on different devices.
-    var bestComputeUnits: MLComputeUnits {
-        return runningOnMac ? .cpuAndGPU : .cpuAndNeuralEngine
-    }
-    
+        
     var reduceMemory: Bool {
         return !runningOnMac
     }
diff --git a/Diffusion/Pipeline/PipelineLoader.swift b/Diffusion/Pipeline/PipelineLoader.swift
index 48597ba..3eafff2 100644
--- a/Diffusion/Pipeline/PipelineLoader.swift
+++ b/Diffusion/Pipeline/PipelineLoader.swift
@@ -97,6 +97,11 @@ extension PipelineLoader {
     var ready: Bool {
         return compiledPath.exists
     }
+    
+    // TODO: measure performance on different devices, disassociate from variant
+    var computeUnits: MLComputeUnits {
+        variant == .original ? .cpuAndGPU : .cpuAndNeuralEngine
+    }
         
     // TODO: maybe receive Progress to add another progress as child
     func prepare() async throws -> Pipeline {
@@ -144,7 +149,7 @@ extension PipelineLoader {
     func load(url: URL) async throws -> StableDiffusionPipeline {
         let beginDate = Date()
         let configuration = MLModelConfiguration()
-        configuration.computeUnits = model.bestComputeUnits
+        configuration.computeUnits = computeUnits
         let pipeline = try StableDiffusionPipeline(resourcesAt: url,
                                                    configuration: configuration,
                                                    disableSafety: false,