diff --git a/externals/coda-oss/.github/workflows/build_unittest.yml b/externals/coda-oss/.github/workflows/build_unittest.yml
index 5f8044cb52..8b6a5dd226 100644
--- a/externals/coda-oss/.github/workflows/build_unittest.yml
+++ b/externals/coda-oss/.github/workflows/build_unittest.yml
@@ -58,7 +58,8 @@ jobs:
         os: [windows-latest]
         platform: [x64]
         configuration: [Debug] # Debug turns on more compiler warnings
-    name: ${{ matrix.os }}-msbuild
+        avx: [AVX2, AVX512F]
+    name: ${{ matrix.os }}-${{ matrix.avx }}-msbuild
     runs-on: ${{ matrix.os }}
 
     steps:
@@ -68,7 +69,7 @@ jobs:
         ls env:
         mkdir out
         cd out
-        cmake .. -DCMAKE_INSTALL_PREFIX=install\${{ matrix.platform }}-${{ matrix.configuration }} -DENABLE_PYTHON=OFF
+        cmake .. -DCMAKE_INSTALL_PREFIX=install\${{ matrix.platform }}-${{ matrix.configuration }} -DENABLE_PYTHON=OFF -DENABLE_${{ matrix.avx }}=ON
     - name: build
       run: |
         cd out
@@ -131,14 +132,15 @@ jobs:
       matrix:
         os: [ubuntu-latest]
         configuration: [Debug, Release]
-    name: ${{ matrix.os }}-${{ matrix.configuration }}-CMake
+        avx: [AVX2, AVX512F]
+    name: ${{ matrix.os }}-${{ matrix.configuration }}-${{ matrix.avx }}-CMake
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v3
     - name: configure
       run: |
         mkdir out && cd out
-        cmake .. -DENABLE_PYTHON=OFF -DENABLE_ASAN=ON
+        cmake .. -DENABLE_PYTHON=OFF -DENABLE_ASAN=ON -DENABLE_${{ matrix.avx }}=ON
     - name: build
       run: |
         cd out
diff --git a/externals/coda-oss/CMakeLists.txt b/externals/coda-oss/CMakeLists.txt
index 4b1bc2c645..f512d520a8 100644
--- a/externals/coda-oss/CMakeLists.txt
+++ b/externals/coda-oss/CMakeLists.txt
@@ -24,19 +24,8 @@ if (${CMAKE_PROJECT_NAME} STREQUAL coda-oss)
     if (MSVC)
        add_compile_options(/WX) # warnings as errors
        add_compile_options(/MP) # multi-processor compile
-
-       if (ENABLE_ASAN)
-            # https://docs.microsoft.com/en-us/cpp/sanitizers/asan?view=msvc-160
-            add_compile_options(/fsanitize=address)
-       endif()
     elseif (UNIX)
        add_compile_options(-Werror) # warnings as errors
-
-       if (ENABLE_ASAN)
-            # https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html
-            add_compile_options(-fsanitize=address)
-            add_link_options(-fsanitize=address)
-       endif()
     endif()
 
     list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
diff --git a/externals/coda-oss/cmake/CodaBuild.cmake b/externals/coda-oss/cmake/CodaBuild.cmake
index 69a143c1b2..1427737888 100644
--- a/externals/coda-oss/cmake/CodaBuild.cmake
+++ b/externals/coda-oss/cmake/CodaBuild.cmake
@@ -165,6 +165,22 @@ macro(coda_initialize_build)
         # This should probably be replaced by GenerateExportHeader
         #set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS TRUE)
         set(CMAKE_VS_INCLUDE_INSTALL_TO_DEFAULT_BUILD TRUE)
+
+       if (ENABLE_ASAN)
+            # https://docs.microsoft.com/en-us/cpp/sanitizers/asan?view=msvc-160
+            add_compile_options(/fsanitize=address)
+       endif()
+
+       # Note SSE2 is implicitly enabled for x64 builds.
+       if (ENABLE_AVX2 AND (NOT ENABLE_AVX512F))
+            # https://learn.microsoft.com/en-us/cpp/build/reference/arch-x86?view=msvc-170
+            add_compile_options(/arch:AVX2)
+       endif()
+       if (ENABLE_AVX512F)
+            # https://learn.microsoft.com/en-us/cpp/build/reference/arch-x86?view=msvc-170
+           add_compile_options(/arch:AVX512)
+       endif()
+
     endif()
 
     # Unix/Linux specific options
@@ -173,6 +189,27 @@ macro(coda_initialize_build)
             -D_LARGEFILE_SOURCE
             -D_FILE_OFFSET_BITS=64
         )
+
+       if (ENABLE_ASAN)
+            # https://gcc.gnu.org/onlinedocs/gcc/Instrumentation-Options.html
+            add_compile_options(-fsanitize=address)
+            add_link_options(-fsanitize=address)
+       endif()
+
+       # Note SSE2 is implicitly enabled for x64 builds.
+       if (ENABLE_AVX2 AND (NOT ENABLE_AVX512F))
+            # https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html
+            # It doesn't look like GCC has a specific option for AVX2;
+            # other projects use "haswell"
+            add_compile_options(-march=haswell)
+       endif()
+       if (ENABLE_AVX512F)
+            # https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html
+            # It doesn't look like GCC has a specific option for AVX512F;
+            # other projects use "native" which isn't quite correct.'
+            add_compile_options(-march=native)
+       endif()
+
     endif()
 
     # all targets should be installed using this export set
diff --git a/externals/coda-oss/modules/c++/avx/unittests/test_m256.cpp b/externals/coda-oss/modules/c++/avx/unittests/test_m256.cpp
index 8c6cdc47b9..920a0f9f8d 100644
--- a/externals/coda-oss/modules/c++/avx/unittests/test_m256.cpp
+++ b/externals/coda-oss/modules/c++/avx/unittests/test_m256.cpp
@@ -25,7 +25,9 @@
 #include <std/cstddef>
 
 #include <sys/Conf.h>
+#include <sys/AbstractOS.h>
 #include <avx/extractf.h>
+#include <config/compiler_extensions.h>
 
 TEST_CASE(extractf)
 {
@@ -49,8 +51,50 @@ TEST_CASE(extractf)
   */
     TEST_SUCCESS;
 }
+
+TEST_CASE(test_getSIMDInstructionSet)
+{
+    // This is the reverse of getSIMDInstructionSet(): it uses the macros to generate a value.
+    constexpr auto simdInstructionSet = sys::getSIMDInstructionSet();
+    #if __AVX512F__
+    static_assert(simdInstructionSet == sys::SIMDInstructionSet::AVX512F, "getSIMDInstructionSet()");
+    #elif __AVX2__
+    static_assert(simdInstructionSet == sys::SIMDInstructionSet::AVX2, "getSIMDInstructionSet()");
+    #else
+    static_assert(simdInstructionSet == sys::SIMDInstructionSet::SSE2, "getSIMDInstructionSet()");
+    #endif
     
+    CODA_OSS_disable_warning_push
+    #if _MSC_VER
+    #pragma warning(disable: 4127) // conditional expression is constant
+    #endif
+
+    switch (sys::getSIMDInstructionSet()) // run-time value
+    {
+    case sys::SIMDInstructionSet::SSE2:
+    {
+        TEST_ASSERT(simdInstructionSet == sys::SIMDInstructionSet::SSE2);
+        break;
+    }
+    case sys::SIMDInstructionSet::AVX2:
+    {
+        TEST_ASSERT(simdInstructionSet == sys::SIMDInstructionSet::AVX2);
+        break;
+    }
+    case sys::SIMDInstructionSet::AVX512F:
+    {
+        TEST_ASSERT(simdInstructionSet == sys::SIMDInstructionSet::AVX512F);
+        break;
+    }
+    default:
+    {
+        TEST_FAIL;
+    }
+    }
+    CODA_OSS_disable_warning_pop
+}
 
 TEST_MAIN(
     TEST_CHECK(extractf);
+    TEST_CHECK(test_getSIMDInstructionSet);
 )
diff --git a/externals/nitro/modules/c/nrt/unittests/test_buffer_adapter.c b/externals/nitro/modules/c/nrt/unittests/test_buffer_adapter.c
index 8c6e5dce8e..186b86aff4 100644
--- a/externals/nitro/modules/c/nrt/unittests/test_buffer_adapter.c
+++ b/externals/nitro/modules/c/nrt/unittests/test_buffer_adapter.c
@@ -44,6 +44,8 @@ TEST_CASE(testReadInBounds)
     {
         TEST_ASSERT(output[ii] == (char)1);
     }
+
+    nrt_IOInterface_destruct(&reader);
 }
 
 TEST_CASE(testReadPastEnd)
@@ -63,6 +65,8 @@ TEST_CASE(testReadPastEnd)
     nrt_IOInterface_seek(reader, 8, NRT_SEEK_SET, &error);
     success = nrt_IOInterface_read(reader, output, sizeof(output), &error);
     TEST_ASSERT(!success);
+
+    nrt_IOInterface_destruct(&reader);
 }
 
 TEST_CASE(testReadOutOfBounds)
@@ -82,6 +86,8 @@ TEST_CASE(testReadOutOfBounds)
     TEST_ASSERT(success != 0);
     success = nrt_IOInterface_read(reader, output, sizeof(output), &error);
     TEST_ASSERT(!success);
+
+    nrt_IOInterface_destruct(&reader);
 }
 
 TEST_CASE(testWriteOutOfBounds)
@@ -99,11 +105,11 @@ TEST_CASE(testWriteOutOfBounds)
     TEST_ASSERT(success != 0);
     success = nrt_IOInterface_write(writer, input, 4, &error);
     TEST_ASSERT(!success);
+
+    nrt_IOInterface_destruct(&writer);
 }
 
 TEST_MAIN(
-    (void) argc;
-    (void) argv;
     CHECK(testReadInBounds);
     CHECK(testReadPastEnd);
     CHECK(testReadOutOfBounds);