diff --git a/src/TableCloth.App/Components/IAppUserInterface.cs b/src/TableCloth.App/Components/IAppUserInterface.cs
index f80afd3a..baa25180 100644
--- a/src/TableCloth.App/Components/IAppUserInterface.cs
+++ b/src/TableCloth.App/Components/IAppUserInterface.cs
@@ -11,6 +11,7 @@ public interface IAppUserInterface
 {
     AboutWindow CreateAboutWindow();
     OptionsWindow CreateOptionsWindow(string? initialTabKey = null);
+    PowerSchemeGuideWindow CreatePowerSchemeGuideWindow();
     CatalogPage CreateCatalogPage(string searchKeyword);
     CatalogPageViewModel CreateCatalogPageViewModel(string searchKeyword);
     QuickStartPage CreateQuickStartPage();
diff --git a/src/TableCloth.App/Components/Implementations/AppUserInterface.cs b/src/TableCloth.App/Components/Implementations/AppUserInterface.cs
index 27d01186..9da8b174 100644
--- a/src/TableCloth.App/Components/Implementations/AppUserInterface.cs
+++ b/src/TableCloth.App/Components/Implementations/AppUserInterface.cs
@@ -53,6 +53,9 @@ public InputPasswordWindow CreateInputPasswordWindow()
     public DisclaimerWindow CreateDisclaimerWindow()
         => SetOwnerIfAvailable(serviceProvider.GetRequiredService<DisclaimerWindow>());
 
+    public PowerSchemeGuideWindow CreatePowerSchemeGuideWindow()
+        => SetOwnerIfAvailable(serviceProvider.GetRequiredService<PowerSchemeGuideWindow>());
+
     public SplashScreen CreateSplashScreen()
         => SetOwnerIfAvailable(serviceProvider.GetRequiredService<SplashScreen>());
 
diff --git a/src/TableCloth.App/Components/Implementations/SandboxLauncher.cs b/src/TableCloth.App/Components/Implementations/SandboxLauncher.cs
index c5eb278f..b4a74dd5 100644
--- a/src/TableCloth.App/Components/Implementations/SandboxLauncher.cs
+++ b/src/TableCloth.App/Components/Implementations/SandboxLauncher.cs
@@ -14,6 +14,8 @@ namespace TableCloth.Components.Implementations;
 
 public sealed class SandboxLauncher(
     IAppMessageBox appMessageBox,
+    IAppUserInterface appUserInterface,
+    IApplicationService applicationService,
     ISharedLocations sharedLocations,
     ISandboxBuilder sandboxBuilder,
     ISandboxCleanupManager sandboxCleanupManager,
@@ -49,6 +51,12 @@ public async Task RunSandboxAsync(TableClothConfiguration config, CancellationTo
             return;
         }
 
+        // CPU 최대 성능이 제한(스로틀)되어 있으면, 시스템 메시지 박스 대신 전용 안내 창을 띄워
+        // 클래식(powercfg.cpl)/모던(전원 및 절전) 전원 설정 중 하나를 골라 열 수 있게 안내한다.
+        // 백그라운드에서 호출될 수 있으므로 UI 스레드로 마샬링해 모달로 표시한다(런치는 계속 진행).
+        if (Helpers.IsSandboxCpuLikelyThrottled() == true)
+            applicationService.DispatchInvoke(() => appUserInterface.CreatePowerSchemeGuideWindow().ShowDialog(), []);
+
         if (config.CertPair != null)
         {
             var now = DateTime.Now;
diff --git a/src/TableCloth.App/DependencyInjection/UseTableClothExtensions.cs b/src/TableCloth.App/DependencyInjection/UseTableClothExtensions.cs
index 0441f8d9..0709157a 100644
--- a/src/TableCloth.App/DependencyInjection/UseTableClothExtensions.cs
+++ b/src/TableCloth.App/DependencyInjection/UseTableClothExtensions.cs
@@ -73,6 +73,7 @@ public static IHostApplicationBuilder UseTableCloth(this IHostApplicationBuilder
             .AddWindow<InputPasswordWindow, InputPasswordWindowViewModel>()
             .AddWindow<AboutWindow, AboutWindowViewModel>()
             .AddWindow<OptionsWindow, OptionsWindowViewModel>()
+            .AddWindow<PowerSchemeGuideWindow, PowerSchemeGuideWindowViewModel>()
             .AddWindow<CertSelectWindow, CertSelectWindowViewModel>()
             .AddWindow<MainWindow, MainWindowViewModel>()
             .AddPage<CatalogPage, CatalogPageViewModel>(addPageAsSingleton: true)
diff --git a/src/TableCloth.App/Dialogs/PowerSchemeGuideWindow.xaml b/src/TableCloth.App/Dialogs/PowerSchemeGuideWindow.xaml
new file mode 100644
index 00000000..b7051af6
--- /dev/null
+++ b/src/TableCloth.App/Dialogs/PowerSchemeGuideWindow.xaml
@@ -0,0 +1,99 @@
+<Window x:Class="TableCloth.Dialogs.PowerSchemeGuideWindow"
+        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        xmlns:vm="clr-namespace:TableCloth.ViewModels"
+        xmlns:res="clr-namespace:TableCloth.Resources;assembly=TableCloth.Core"
+        mc:Ignorable="d"
+        Style="{DynamicResource MainWindowStyle}"
+        WindowStyle="SingleBorderWindow" WindowStartupLocation="CenterOwner" ResizeMode="NoResize" ShowInTaskbar="False"
+        Title="{x:Static res:UIStringResources.PowerSchemeGuide_Title}" Width="520" SizeToContent="Height"
+        TextOptions.TextFormattingMode="Display" TextOptions.TextRenderingMode="ClearType"
+        d:DataContext="{d:DesignInstance Type=vm:PowerSchemeGuideWindowViewModelForDesigner, IsDesignTimeCreatable=True}">
+    <Window.Resources>
+        <!-- 옵션 카드 버튼: 테마 기본 Button 템플릿은 ContentPresenter의 HorizontalAlignment를 Center로
+             하드코딩해 HorizontalContentAlignment를 무시한다. 내부 텍스트를 왼쪽 정렬하기 위해
+             ContentPresenter를 Stretch로 두는 로컬 템플릿을 적용한다(테마 색은 DynamicResource로 유지). -->
+        <Style x:Key="OptionCardButtonStyle" TargetType="Button">
+            <Setter Property="Background" Value="{DynamicResource ControlDefaultBackground}" />
+            <Setter Property="BorderBrush" Value="{DynamicResource ControlDefaultBorderBrush}" />
+            <Setter Property="Foreground" Value="{DynamicResource ControlDefaultForeground}" />
+            <Setter Property="BorderThickness" Value="1" />
+            <Setter Property="Cursor" Value="Hand" />
+            <Setter Property="HorizontalContentAlignment" Value="Stretch" />
+            <Setter Property="Template">
+                <Setter.Value>
+                    <ControlTemplate TargetType="Button">
+                        <Border x:Name="border"
+                                BorderBrush="{TemplateBinding BorderBrush}"
+                                BorderThickness="{TemplateBinding BorderThickness}"
+                                Background="{TemplateBinding Background}"
+                                SnapsToDevicePixels="True">
+                            <ContentPresenter Margin="{TemplateBinding Padding}"
+                                              HorizontalAlignment="Stretch"
+                                              VerticalAlignment="Center"
+                                              RecognizesAccessKey="True"
+                                              SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
+                        </Border>
+                        <ControlTemplate.Triggers>
+                            <Trigger Property="IsMouseOver" Value="True">
+                                <Setter TargetName="border" Property="Background" Value="{DynamicResource ControlPrimaryMouseOverBackground}" />
+                                <Setter TargetName="border" Property="BorderBrush" Value="{DynamicResource ControlPrimaryMouseOverBorderBrush}" />
+                            </Trigger>
+                            <Trigger Property="IsPressed" Value="True">
+                                <Setter TargetName="border" Property="Background" Value="{DynamicResource ControlPrimarySelectedBackground}" />
+                                <Setter TargetName="border" Property="BorderBrush" Value="{DynamicResource ControlPrimarySelectedBorderBrush}" />
+                            </Trigger>
+                        </ControlTemplate.Triggers>
+                    </ControlTemplate>
+                </Setter.Value>
+            </Setter>
+        </Style>
+    </Window.Resources>
+    <Grid Margin="18">
+        <Grid.RowDefinitions>
+            <RowDefinition Height="Auto" />
+            <RowDefinition Height="Auto" />
+            <RowDefinition Height="Auto" />
+            <RowDefinition Height="Auto" />
+            <RowDefinition Height="Auto" />
+        </Grid.RowDefinitions>
+
+        <TextBlock Grid.Row="0" Margin="0 0 0 8" FontSize="16" FontWeight="SemiBold" TextWrapping="Wrap"
+                   Text="{x:Static res:UIStringResources.PowerSchemeGuide_Heading}" />
+
+        <TextBlock Grid.Row="1" Margin="0 0 0 14" TextWrapping="Wrap"
+                   Foreground="{DynamicResource ControlSecondaryForeground}"
+                   Text="{x:Static res:UIStringResources.PowerSchemeGuide_Body}" />
+
+        <!-- 클래식 제어판(powercfg.cpl). 열기만 하고 이 안내 창은 그대로 유지된다. -->
+        <Button Grid.Row="2" Margin="0 0 0 8" Padding="14 10" Style="{StaticResource OptionCardButtonStyle}"
+                Command="{Binding OpenClassicPowerOptionsCommand}">
+            <StackPanel>
+                <TextBlock FontWeight="SemiBold" TextWrapping="Wrap" TextAlignment="Left"
+                           Text="{x:Static res:UIStringResources.PowerSchemeGuide_OpenClassicButton}" />
+                <TextBlock Margin="0 3 0 0" FontSize="11" TextWrapping="Wrap" TextAlignment="Left"
+                           Foreground="{DynamicResource ControlSecondaryForeground}"
+                           Text="{x:Static res:UIStringResources.PowerSchemeGuide_OpenClassicDescription}" />
+            </StackPanel>
+        </Button>
+
+        <!-- 모던 설정(전원 및 절전). 열기만 하고 이 안내 창은 그대로 유지된다. -->
+        <Button Grid.Row="3" Margin="0 0 0 16" Padding="14 10" Style="{StaticResource OptionCardButtonStyle}"
+                Command="{Binding OpenModernPowerSettingsCommand}">
+            <StackPanel>
+                <TextBlock FontWeight="SemiBold" TextWrapping="Wrap" TextAlignment="Left"
+                           Text="{x:Static res:UIStringResources.PowerSchemeGuide_OpenModernButton}" />
+                <TextBlock Margin="0 3 0 0" FontSize="11" TextWrapping="Wrap" TextAlignment="Left"
+                           Foreground="{DynamicResource ControlSecondaryForeground}"
+                           Text="{x:Static res:UIStringResources.PowerSchemeGuide_OpenModernDescription}" />
+            </StackPanel>
+        </Button>
+
+        <StackPanel Grid.Row="4" Orientation="Horizontal" HorizontalAlignment="Right">
+            <Button Padding="16 6" Content="{x:Static res:UIStringResources.PowerSchemeGuide_CloseButton}"
+                    Command="{Binding DismissCommand}" IsCancel="True" IsDefault="True" />
+        </StackPanel>
+    </Grid>
+</Window>
diff --git a/src/TableCloth.App/Dialogs/PowerSchemeGuideWindow.xaml.cs b/src/TableCloth.App/Dialogs/PowerSchemeGuideWindow.xaml.cs
new file mode 100644
index 00000000..8f6af55f
--- /dev/null
+++ b/src/TableCloth.App/Dialogs/PowerSchemeGuideWindow.xaml.cs
@@ -0,0 +1,22 @@
+using System;
+using System.Windows;
+using TableCloth.ViewModels;
+
+namespace TableCloth.Dialogs;
+
+public partial class PowerSchemeGuideWindow : Window
+{
+    public PowerSchemeGuideWindow(
+        PowerSchemeGuideWindowViewModel viewModel)
+    {
+        InitializeComponent();
+        DataContext = viewModel;
+        viewModel.CloseRequested += ViewModel_CloseRequested;
+    }
+
+    public PowerSchemeGuideWindowViewModel ViewModel
+        => (PowerSchemeGuideWindowViewModel)DataContext;
+
+    private void ViewModel_CloseRequested(object? sender, EventArgs e)
+        => Close();
+}
diff --git a/src/TableCloth.App/ViewModels/PowerSchemeGuideWindowViewModel.cs b/src/TableCloth.App/ViewModels/PowerSchemeGuideWindowViewModel.cs
new file mode 100644
index 00000000..541fcba1
--- /dev/null
+++ b/src/TableCloth.App/ViewModels/PowerSchemeGuideWindowViewModel.cs
@@ -0,0 +1,66 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using Microsoft.Extensions.DependencyInjection;
+using System;
+using System.Diagnostics;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace TableCloth.ViewModels;
+
+[Obsolete("This class is reserved for design-time usage.", false)]
+public partial class PowerSchemeGuideWindowViewModelForDesigner : PowerSchemeGuideWindowViewModel { }
+
+/// <summary>
+/// CPU 최대 성능(최대 프로세서 상태)이 제한되어 Windows Sandbox가 느려질 수 있음을 안내하고,
+/// 사용자가 클래식 제어판(<c>powercfg.cpl</c>) 또는 모던 설정(전원 및 절전) 중 하나를 골라 열 수 있게 하는
+/// 안내 창의 뷰모델. 전원 옵션을 여는 커맨드는 창을 닫지 않고 그대로 유지하며(사용자가 확인 후 직접 닫음),
+/// '나중에'만 창을 닫는다. 여는 데 실패해도 무해하다(베스트에포트).
+/// </summary>
+public partial class PowerSchemeGuideWindowViewModel : ObservableObject
+{
+    protected PowerSchemeGuideWindowViewModel() { }
+
+    [ActivatorUtilitiesConstructor]
+    public PowerSchemeGuideWindowViewModel(
+        TaskFactory taskFactory)
+    {
+        _taskFactory = taskFactory;
+    }
+
+    private readonly TaskFactory _taskFactory = default!;
+
+    /// <summary>안내 창을 닫아 달라는 요청. 코드 비하인드가 구독해 <c>Close()</c>를 호출한다.</summary>
+    public event EventHandler? CloseRequested;
+
+    private async Task RequestCloseAsync()
+        => await _taskFactory.StartNew(() => CloseRequested?.Invoke(this, EventArgs.Empty)).ConfigureAwait(false);
+
+    /// <summary>클래식 제어판의 전원 옵션(powercfg.cpl)을 연다. 안내 창은 닫지 않고 그대로 둔다.</summary>
+    [RelayCommand]
+    private void OpenClassicPowerOptions()
+        // control.exe 로 .cpl 을 여는 것이 셸 연결에 의존하지 않아 안정적이다.
+        => TryStart(new ProcessStartInfo("control.exe", "powercfg.cpl") { UseShellExecute = true });
+
+    /// <summary>모던 Windows 설정의 전원 페이지(전원 및 절전)를 연다. 안내 창은 닫지 않고 그대로 둔다.</summary>
+    [RelayCommand]
+    private void OpenModernPowerSettings()
+        => TryStart(new ProcessStartInfo("ms-settings:powersleep") { UseShellExecute = true });
+
+    /// <summary>아무 것도 열지 않고 안내 창을 닫는다(나중에).</summary>
+    [RelayCommand]
+    private async Task Dismiss()
+        => await RequestCloseAsync();
+
+    private static void TryStart(ProcessStartInfo startInfo)
+    {
+        try
+        {
+            Process.Start(startInfo);
+        }
+        catch
+        {
+            // 외부 설정 페이지 열기는 보조 동작이므로 실패해도 조용히 무시한다.
+        }
+    }
+}
diff --git a/src/TableCloth.Core/Helpers.cs b/src/TableCloth.Core/Helpers.cs
index db84c16e..4f9b726b 100644
--- a/src/TableCloth.Core/Helpers.cs
+++ b/src/TableCloth.Core/Helpers.cs
@@ -3,6 +3,7 @@
 using System.IO;
 using System.Linq;
 using System.Reflection;
+using System.Runtime.InteropServices;
 using System.Text;
 
 #nullable enable
@@ -11,6 +12,140 @@ namespace TableCloth
 {
     public static class Helpers
     {
+        // 전원 관리 옵션 "이름(GUID)"이 아니라, 활성 옵션의 실제 CPU 성능 상한(최대 프로세서 상태)을 읽어
+        // 판단한다. 이름 기반 판별은 복제/OEM 커스텀 옵션을 오탐하고, AC의 '균형 조정'처럼 실제로는
+        // 100%로 동작하는 경우도 잘못 경고했다. 여기서는 현재 전원 소스(AC/DC)의 최대 프로세서 상태를
+        // 그대로 읽어, CPU가 실제로 제한(스로틀)될 때만(=100% 미만) Windows Sandbox 성능 저하로 판정한다.
+
+        /// <summary>Windows 프로세서 전원 관리 하위 그룹 GUID(GUID_PROCESSOR_SETTINGS_SUBGROUP).</summary>
+        private static readonly Guid ProcessorSettingsSubgroupGuid =
+            new Guid("54533251-82be-4824-96c1-47b60b740d00");
+
+        /// <summary>"최대 프로세서 상태" 설정 GUID(GUID_PROCESSOR_THROTTLE_MAXIMUM). 값은 0~100(%).</summary>
+        private static readonly Guid ProcessorThrottleMaximumSettingGuid =
+            new Guid("bc5038f7-23e0-4960-96da-33abaf5935ec");
+
+        private const uint ERROR_SUCCESS = 0u;
+
+        /// <summary>제한이 없는(=최고 성능) 최대 프로세서 상태 값(%).</summary>
+        private const int FullProcessorStatePercent = 100;
+
+        [DllImport("powrprof.dll", SetLastError = true)]
+        private static extern uint PowerGetActiveScheme(IntPtr userRootPowerKey, out IntPtr activePolicyGuid);
+
+        [DllImport("powrprof.dll")]
+        private static extern uint PowerReadACValueIndex(
+            IntPtr rootPowerKey, in Guid schemeGuid, in Guid subGroupOfPowerSettingsGuid,
+            in Guid powerSettingGuid, out uint acValueIndex);
+
+        [DllImport("powrprof.dll")]
+        private static extern uint PowerReadDCValueIndex(
+            IntPtr rootPowerKey, in Guid schemeGuid, in Guid subGroupOfPowerSettingsGuid,
+            in Guid powerSettingGuid, out uint dcValueIndex);
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        private static extern IntPtr LocalFree(IntPtr hMem);
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        [return: MarshalAs(UnmanagedType.Bool)]
+        private static extern bool GetSystemPowerStatus(out SYSTEM_POWER_STATUS lpSystemPowerStatus);
+
+        [StructLayout(LayoutKind.Sequential)]
+        private struct SYSTEM_POWER_STATUS
+        {
+            public byte ACLineStatus;       // 0 = 배터리(오프라인), 1 = AC(온라인), 255 = 알 수 없음
+            public byte BatteryFlag;
+            public byte BatteryLifePercent;
+            public byte SystemStatusFlag;
+            public int BatteryLifeTime;
+            public int BatteryFullLifeTime;
+        }
+
+        /// <summary>
+        /// 최대 프로세서 상태 값(%)이 "제한됨(스로틀)"에 해당하는지 여부를 반환하는 순수 함수.
+        /// 100% 미만이면 CPU 성능이 상한으로 제한된 것으로 본다.
+        /// </summary>
+        public static bool IsProcessorStateThrottled(int maxProcessorStatePercent)
+            => maxProcessorStatePercent < FullProcessorStatePercent;
+
+        /// <summary>
+        /// 호스트에서 현재 활성화된 전원 관리 옵션의 GUID를 <c>PowerGetActiveScheme</c>로 읽는다.
+        /// 읽기에 실패하면 <see langword="null"/>을 반환한다.
+        /// </summary>
+        public static Guid? GetActivePowerSchemeGuid()
+        {
+            var activePolicyGuidPtr = IntPtr.Zero;
+
+            try
+            {
+                if (PowerGetActiveScheme(IntPtr.Zero, out activePolicyGuidPtr) != ERROR_SUCCESS)
+                    return null;
+
+                if (activePolicyGuidPtr == IntPtr.Zero)
+                    return null;
+
+                return Marshal.PtrToStructure<Guid>(activePolicyGuidPtr);
+            }
+            catch
+            {
+                return null;
+            }
+            finally
+            {
+                if (activePolicyGuidPtr != IntPtr.Zero)
+                    LocalFree(activePolicyGuidPtr);
+            }
+        }
+
+        /// <summary>현재 배터리(DC)로 실행 중인지 여부. 판별 불가/AC면 <see langword="false"/>.</summary>
+        private static bool IsRunningOnBattery()
+        {
+            if (!GetSystemPowerStatus(out var status))
+                return false;
+
+            // 0 = 배터리. 1(AC)/255(알 수 없음)은 AC로 간주해 AC 설정을 읽는다(보수적).
+            return status.ACLineStatus == 0;
+        }
+
+        /// <summary>
+        /// 현재 전원 소스(AC 또는 배터리)에 적용되는 활성 옵션의 "최대 프로세서 상태"(%)를 읽는다.
+        /// 읽기에 실패하면 <see langword="null"/>을 반환한다.
+        /// </summary>
+        public static int? GetActiveMaxProcessorStatePercent()
+        {
+            var activeSchemeGuid = GetActivePowerSchemeGuid();
+            if (!activeSchemeGuid.HasValue)
+                return null;
+
+            var schemeGuid = activeSchemeGuid.Value;
+
+            var result = IsRunningOnBattery()
+                ? PowerReadDCValueIndex(IntPtr.Zero, in schemeGuid, in ProcessorSettingsSubgroupGuid,
+                    in ProcessorThrottleMaximumSettingGuid, out var value)
+                : PowerReadACValueIndex(IntPtr.Zero, in schemeGuid, in ProcessorSettingsSubgroupGuid,
+                    in ProcessorThrottleMaximumSettingGuid, out value);
+
+            if (result != ERROR_SUCCESS)
+                return null;
+
+            return (int)value;
+        }
+
+        /// <summary>
+        /// 호스트의 CPU 최대 성능이 제한(스로틀)되어 Windows Sandbox가 느려질 가능성이 높은지 여부를 반환한다.
+        /// 현재 전원 소스의 최대 프로세서 상태가 100% 미만이면 <see langword="true"/>. 판별에 실패하면
+        /// (예: 지원되지 않는 환경) <see langword="null"/>을 반환해, 확신할 때만 경고하도록 한다.
+        /// </summary>
+        public static bool? IsSandboxCpuLikelyThrottled()
+        {
+            var maxProcessorStatePercent = GetActiveMaxProcessorStatePercent();
+
+            if (!maxProcessorStatePercent.HasValue)
+                return null;
+
+            return IsProcessorStateThrottled(maxProcessorStatePercent.Value);
+        }
+
         public static bool IsDevelopmentBuild =>
 #if DEBUG
             true
diff --git a/src/TableCloth.Core/Resources/UIStringResources.Designer.cs b/src/TableCloth.Core/Resources/UIStringResources.Designer.cs
index 58cf6985..aedcb7be 100644
--- a/src/TableCloth.Core/Resources/UIStringResources.Designer.cs
+++ b/src/TableCloth.Core/Resources/UIStringResources.Designer.cs
@@ -1984,6 +1984,54 @@ public static string QuickStart_DataDirectory_OpenMissingPrompt {
             }
         }
 
+        public static string PowerSchemeGuide_Title {
+            get {
+                return ResourceManager.GetString("PowerSchemeGuide_Title", resourceCulture);
+            }
+        }
+
+        public static string PowerSchemeGuide_Heading {
+            get {
+                return ResourceManager.GetString("PowerSchemeGuide_Heading", resourceCulture);
+            }
+        }
+
+        public static string PowerSchemeGuide_Body {
+            get {
+                return ResourceManager.GetString("PowerSchemeGuide_Body", resourceCulture);
+            }
+        }
+
+        public static string PowerSchemeGuide_OpenClassicButton {
+            get {
+                return ResourceManager.GetString("PowerSchemeGuide_OpenClassicButton", resourceCulture);
+            }
+        }
+
+        public static string PowerSchemeGuide_OpenClassicDescription {
+            get {
+                return ResourceManager.GetString("PowerSchemeGuide_OpenClassicDescription", resourceCulture);
+            }
+        }
+
+        public static string PowerSchemeGuide_OpenModernButton {
+            get {
+                return ResourceManager.GetString("PowerSchemeGuide_OpenModernButton", resourceCulture);
+            }
+        }
+
+        public static string PowerSchemeGuide_OpenModernDescription {
+            get {
+                return ResourceManager.GetString("PowerSchemeGuide_OpenModernDescription", resourceCulture);
+            }
+        }
+
+        public static string PowerSchemeGuide_CloseButton {
+            get {
+                return ResourceManager.GetString("PowerSchemeGuide_CloseButton", resourceCulture);
+            }
+        }
+
         public static string Options_Title {
             get {
                 return ResourceManager.GetString("Options_Title", resourceCulture);
diff --git a/src/TableCloth.Core/Resources/UIStringResources.ko.resx b/src/TableCloth.Core/Resources/UIStringResources.ko.resx
index e433e6b6..c04bfbf3 100644
--- a/src/TableCloth.Core/Resources/UIStringResources.ko.resx
+++ b/src/TableCloth.Core/Resources/UIStringResources.ko.resx
@@ -865,6 +865,30 @@ https://github.com/yourtablecloth/TableCloth</value>
 
 지금 만들어서 열까요?</value>
   </data>
+  <data name="PowerSchemeGuide_Title" xml:space="preserve">
+    <value>Windows Sandbox 성능 안내</value>
+  </data>
+  <data name="PowerSchemeGuide_Heading" xml:space="preserve">
+    <value>현재 CPU 최대 성능이 제한되어 있습니다</value>
+  </data>
+  <data name="PowerSchemeGuide_Body" xml:space="preserve">
+    <value>최대 프로세서 상태가 100% 미만으로 설정되어 있어(절전 모드이거나 배터리로 실행 중일 수 있습니다) Windows Sandbox 시작과 실행이 느려질 수 있습니다. 더 쾌적하게 사용하려면 전원(AC)에 연결하거나 최대 프로세서 상태를 높여 주세요. 아래에서 전원 설정을 바로 열 수 있습니다.</value>
+  </data>
+  <data name="PowerSchemeGuide_OpenClassicButton" xml:space="preserve">
+    <value>제어판 전원 옵션 열기 (powercfg.cpl)</value>
+  </data>
+  <data name="PowerSchemeGuide_OpenClassicDescription" xml:space="preserve">
+    <value>전원 관리 옵션을 변경하거나 사용자 지정할 수 있는 기존 제어판 창을 엽니다.</value>
+  </data>
+  <data name="PowerSchemeGuide_OpenModernButton" xml:space="preserve">
+    <value>설정 열기 (전원 및 절전)</value>
+  </data>
+  <data name="PowerSchemeGuide_OpenModernDescription" xml:space="preserve">
+    <value>Windows 설정의 최신 전원 페이지를 엽니다.</value>
+  </data>
+  <data name="PowerSchemeGuide_CloseButton" xml:space="preserve">
+    <value>나중에</value>
+  </data>
   <data name="Options_Title" xml:space="preserve">
     <value>옵션</value>
   </data>
diff --git a/src/TableCloth.Core/Resources/UIStringResources.resx b/src/TableCloth.Core/Resources/UIStringResources.resx
index 4e123112..cff439c7 100644
--- a/src/TableCloth.Core/Resources/UIStringResources.resx
+++ b/src/TableCloth.Core/Resources/UIStringResources.resx
@@ -866,6 +866,30 @@ Create it now and continue?</value>
 
 Create it and open it now?</value>
   </data>
+  <data name="PowerSchemeGuide_Title" xml:space="preserve">
+    <value>Windows Sandbox performance notice</value>
+  </data>
+  <data name="PowerSchemeGuide_Heading" xml:space="preserve">
+    <value>Your CPU's maximum performance is currently limited</value>
+  </data>
+  <data name="PowerSchemeGuide_Body" xml:space="preserve">
+    <value>The maximum processor state is set below 100% (for example, a power-saver plan or running on battery), so Windows Sandbox may start and run slowly. For a smoother experience, connect to AC power or raise the maximum processor state. You can open the power settings below.</value>
+  </data>
+  <data name="PowerSchemeGuide_OpenClassicButton" xml:space="preserve">
+    <value>Open Control Panel power options (powercfg.cpl)</value>
+  </data>
+  <data name="PowerSchemeGuide_OpenClassicDescription" xml:space="preserve">
+    <value>Opens the classic Power Options window, where you can switch or customize your power plan.</value>
+  </data>
+  <data name="PowerSchemeGuide_OpenModernButton" xml:space="preserve">
+    <value>Open Settings (Power &amp; sleep)</value>
+  </data>
+  <data name="PowerSchemeGuide_OpenModernDescription" xml:space="preserve">
+    <value>Opens the modern Windows Settings power page.</value>
+  </data>
+  <data name="PowerSchemeGuide_CloseButton" xml:space="preserve">
+    <value>Later</value>
+  </data>
   <data name="Options_Title" xml:space="preserve">
     <value>Options</value>
   </data>
diff --git a/src/TableCloth.Test/ProcessorThrottleTests.cs b/src/TableCloth.Test/ProcessorThrottleTests.cs
new file mode 100644
index 00000000..1da98afc
--- /dev/null
+++ b/src/TableCloth.Test/ProcessorThrottleTests.cs
@@ -0,0 +1,45 @@
+using TableCloth;
+
+namespace TableCloth.Test
+{
+    /// <summary>
+    /// 전원 옵션 "이름"이 아니라 실제 CPU 최대 성능 상한(최대 프로세서 상태, %)으로 스로틀 여부를 판정하는
+    /// 순수 분류기(<see cref="Helpers.IsProcessorStateThrottled(int)"/>)를 검증한다. 실제 P/Invoke 판독은
+    /// 환경 의존적이라 여기서는 다루지 않고, 값 → 판정 로직만 확인한다.
+    /// </summary>
+    [TestClass]
+    public sealed class ProcessorThrottleTests
+    {
+        [TestMethod]
+        public void IsProcessorStateThrottled_FullHundredPercent_ReturnsFalse()
+        {
+            // AC의 '균형 조정'을 포함해 최대 프로세서 상태가 100%면 제한되지 않은 것으로 본다(경고 안 함).
+            Assert.IsFalse(Helpers.IsProcessorStateThrottled(100));
+        }
+
+        [TestMethod]
+        public void IsProcessorStateThrottled_JustBelowHundred_ReturnsTrue()
+        {
+            Assert.IsTrue(Helpers.IsProcessorStateThrottled(99));
+        }
+
+        [TestMethod]
+        public void IsProcessorStateThrottled_Half_ReturnsTrue()
+        {
+            Assert.IsTrue(Helpers.IsProcessorStateThrottled(50));
+        }
+
+        [TestMethod]
+        public void IsProcessorStateThrottled_Zero_ReturnsTrue()
+        {
+            Assert.IsTrue(Helpers.IsProcessorStateThrottled(0));
+        }
+
+        [TestMethod]
+        public void IsProcessorStateThrottled_AboveHundred_ReturnsFalse()
+        {
+            // 100을 초과하는 값은 발생하지 않지만, 방어적으로 "제한 아님"으로 처리한다.
+            Assert.IsFalse(Helpers.IsProcessorStateThrottled(101));
+        }
+    }
+}