diff --git a/src/VirtualClient/VirtualClient.Core.UnitTests/ProfileExpressionEvaluatorTests.cs b/src/VirtualClient/VirtualClient.Core.UnitTests/ProfileExpressionEvaluatorTests.cs
index 30c2f4a535..d1df807424 100644
--- a/src/VirtualClient/VirtualClient.Core.UnitTests/ProfileExpressionEvaluatorTests.cs
+++ b/src/VirtualClient/VirtualClient.Core.UnitTests/ProfileExpressionEvaluatorTests.cs
@@ -1714,6 +1714,28 @@ public async Task ProfileExpressionEvaluatorSupportsNestedTernaryFunctionReferen
             Assert.AreEqual(expectedValue, parameters["Flags"]);
         }
 
+        [Test]
+        // On Windows the SPECcpu toolchain is always the x86_64 Cygwin GCC (there is no Arm64 Cygwin), so
+        // '-march=armv8-a' is invalid and must resolve to 'native' even on win-arm64. Only linux-arm64 uses 'armv8-a'.
+        [TestCase(PlatformID.Win32NT, Architecture.Arm64, "-g -O3 -march=native -frecord-gcc-switches")]
+        [TestCase(PlatformID.Win32NT, Architecture.X64, "-g -O3 -march=native -frecord-gcc-switches")]
+        [TestCase(PlatformID.Unix, Architecture.X64, "-g -O3 -march=native -frecord-gcc-switches")]
+        [TestCase(PlatformID.Unix, Architecture.Arm64, "-g -O3 -march=armv8-a -frecord-gcc-switches")]
+        public async Task ProfileExpressionEvaluatorResolvesSpecCpuOptimizingFlagsForEachPlatform(PlatformID platform, Architecture architecture, string expectedValue)
+        {
+            this.SetupDefaults(platform, architecture);
+            Dictionary<string, IConvertible> parameters = new Dictionary<string, IConvertible>
+            {
+                {
+                    "BaseOptimizingFlags",
+                    "-g -O3 -march={calculate((\"{Platform}\".StartsWith(\"win\") || \"{Architecture}\" == \"x64\") ? \"native\" : \"armv8-a\")} -frecord-gcc-switches"
+                }
+            };
+
+            await ProfileExpressionEvaluator.Instance.EvaluateAsync(this.mockFixture.Dependencies, parameters);
+            Assert.AreEqual(expectedValue, parameters["BaseOptimizingFlags"]);
+        }
+
         [Test]
         public async Task ProfileExpressionEvaluatorSupportsPathBasedFunctionAndComparisonOperations_Scenario_1()
         {
diff --git a/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-FPRATE.json b/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-FPRATE.json
index 9ff9b81cf5..54aec9fd27 100644
--- a/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-FPRATE.json
+++ b/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-FPRATE.json
@@ -19,8 +19,8 @@
         "RunPeak": false,
         "Threads": "{LogicalCoreCount}",
         "Copies": "{LogicalCoreCount}",
-        "BaseOptimizingFlags": "-g -O3 -march={calculate(\"{Architecture}\" == \"x64\" ? \"native\" : \"armv8-a\")} -frecord-gcc-switches",
-        "PeakOptimizingFlags": "-g -Ofast -march={calculate(\"{Architecture}\" == \"x64\" ? \"native\" : \"armv8-a\")} -flto -frecord-gcc-switches"
+        "BaseOptimizingFlags": "-g -O3 -march={calculate((\"{Platform}\".StartsWith(\"win\") || \"{Architecture}\" == \"x64\") ? \"native\" : \"armv8-a\")} -frecord-gcc-switches",
+        "PeakOptimizingFlags": "-g -Ofast -march={calculate((\"{Platform}\".StartsWith(\"win\") || \"{Architecture}\" == \"x64\") ? \"native\" : \"armv8-a\")} -flto -frecord-gcc-switches"
     },
     "Actions": [
         {
diff --git a/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-FPSPEED.json b/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-FPSPEED.json
index 9a8de1eee1..7620a07ba0 100644
--- a/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-FPSPEED.json
+++ b/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-FPSPEED.json
@@ -19,8 +19,8 @@
         "RunPeak": false,
         "Threads": "{LogicalCoreCount}",
         "Copies": "{LogicalCoreCount}",
-        "BaseOptimizingFlags": "-g -O3 -march={calculate(\"{Architecture}\" == \"x64\" ? \"native\" : \"armv8-a\")} -frecord-gcc-switches",
-        "PeakOptimizingFlags": "-g -Ofast -march={calculate(\"{Architecture}\" == \"x64\" ? \"native\" : \"armv8-a\")} -flto -frecord-gcc-switches"
+        "BaseOptimizingFlags": "-g -O3 -march={calculate((\"{Platform}\".StartsWith(\"win\") || \"{Architecture}\" == \"x64\") ? \"native\" : \"armv8-a\")} -frecord-gcc-switches",
+        "PeakOptimizingFlags": "-g -Ofast -march={calculate((\"{Platform}\".StartsWith(\"win\") || \"{Architecture}\" == \"x64\") ? \"native\" : \"armv8-a\")} -flto -frecord-gcc-switches"
     },
     "Actions": [
         {
diff --git a/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-INTRATE.json b/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-INTRATE.json
index 8c809a07ab..844f93d5db 100644
--- a/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-INTRATE.json
+++ b/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-INTRATE.json
@@ -19,8 +19,8 @@
         "RunPeak": false,
         "Threads": "{LogicalCoreCount}",
         "Copies": "{LogicalCoreCount}",
-        "BaseOptimizingFlags": "-g -O3 -march={calculate(\"{Architecture}\" == \"x64\" ? \"native\" : \"armv8-a\")} -frecord-gcc-switches",
-        "PeakOptimizingFlags": "-g -Ofast -march={calculate(\"{Architecture}\" == \"x64\" ? \"native\" : \"armv8-a\")} -flto -frecord-gcc-switches"
+        "BaseOptimizingFlags": "-g -O3 -march={calculate((\"{Platform}\".StartsWith(\"win\") || \"{Architecture}\" == \"x64\") ? \"native\" : \"armv8-a\")} -frecord-gcc-switches",
+        "PeakOptimizingFlags": "-g -Ofast -march={calculate((\"{Platform}\".StartsWith(\"win\") || \"{Architecture}\" == \"x64\") ? \"native\" : \"armv8-a\")} -flto -frecord-gcc-switches"
     },
     "Actions": [
         {
diff --git a/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-INTSPEED.json b/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-INTSPEED.json
index 7f15a3e3bb..e2dc3a04d3 100644
--- a/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-INTSPEED.json
+++ b/src/VirtualClient/VirtualClient.Main/profiles/PERF-SPECCPU-INTSPEED.json
@@ -19,8 +19,8 @@
         "RunPeak": false,
         "Threads": "{LogicalCoreCount}",
         "Copies": "{LogicalCoreCount}",
-        "BaseOptimizingFlags": "-g -O3 -march={calculate(\"{Architecture}\" == \"x64\" ? \"native\" : \"armv8-a\")} -frecord-gcc-switches",
-        "PeakOptimizingFlags": "-g -Ofast -march={calculate(\"{Architecture}\" == \"x64\" ? \"native\" : \"armv8-a\")} -flto -frecord-gcc-switches"
+        "BaseOptimizingFlags": "-g -O3 -march={calculate((\"{Platform}\".StartsWith(\"win\") || \"{Architecture}\" == \"x64\") ? \"native\" : \"armv8-a\")} -frecord-gcc-switches",
+        "PeakOptimizingFlags": "-g -Ofast -march={calculate((\"{Platform}\".StartsWith(\"win\") || \"{Architecture}\" == \"x64\") ? \"native\" : \"armv8-a\")} -flto -frecord-gcc-switches"
     },
     "Actions": [
         {