diff --git a/.github/workflows/master_build.yml b/.github/workflows/master_build.yml
index 6392a1f08f..9a80ca4f05 100644
--- a/.github/workflows/master_build.yml
+++ b/.github/workflows/master_build.yml
@@ -64,7 +64,7 @@ jobs:
           echo "PYTHON_EXEC=python3" >> $GITHUB_ENV
           echo "INSTALLER_EXT=tgz" >> $GITHUB_ENV
           echo "CMAKE_BUILD_EXTRA=-- -j$(nproc)" >> $GITHUB_ENV
-          echo "CMAKE_EXTRA=-DVIRCADIA_CPU_ARCHITECTURE= -DBUILD_TOOLS:BOOLEAN=FALSE -DHIFI_PYTHON_EXEC:FILEPATH=$(which python3)" >> $GITHUB_ENV
+          echo "CMAKE_EXTRA=-DVIRCADIA_CPU_ARCHITECTURE=-msse3 -DBUILD_TOOLS:BOOLEAN=FALSE -DHIFI_PYTHON_EXEC:FILEPATH=$(which python3)" >> $GITHUB_ENV
         fi
         # Mac build variables
         if [ "${{ matrix.os }}" = "macOS-10.15" ]; then
diff --git a/.github/workflows/pr_build.yml b/.github/workflows/pr_build.yml
index f7cc05dc80..76e7424c35 100644
--- a/.github/workflows/pr_build.yml
+++ b/.github/workflows/pr_build.yml
@@ -73,21 +73,33 @@ jobs:
           echo "PYTHON_EXEC=python3" >> $GITHUB_ENV
           echo "INSTALLER_EXT=*" >> $GITHUB_ENV
           echo "CMAKE_BUILD_EXTRA=-- -j$(nproc)" >> $GITHUB_ENV
+          # Variables specific to our aarch64 runner
           if [ "${{ matrix.os }}" = "self-hosted_debian-11_aarch64" ]; then
             echo "VIRCADIA_USE_SYSTEM_QT=true" >> $GITHUB_ENV
             echo "CI_WORKSPACE=${{runner.workspace}}" >> $GITHUB_ENV
             # Don't optimize builds to save build time.
             echo "VIRCADIA_OPTIMIZE=false" >> $GITHUB_ENV
           fi
+
           if [[ "${{ matrix.os }}" = *"aarch64" ]]; then
             echo "VCPKG_FORCE_SYSTEM_BINARIES=true" >> $GITHUB_ENV
+            if [ "${{ matrix.build_type }}" = "full" ]; then
+              echo "CMAKE_EXTRA=-DVIRCADIA_CPU_ARCHITECTURE= -DBUILD_TOOLS:BOOLEAN=FALSE -DHIFI_PYTHON_EXEC:FILEPATH=$(which python3)" >> $GITHUB_ENV
+            else
+              echo "CMAKE_EXTRA=-DVIRCADIA_CPU_ARCHITECTURE= -DCLIENT_ONLY=1 -DBUILD_TOOLS:BOOLEAN=FALSE -DHIFI_PYTHON_EXEC:FILEPATH=$(which python3)" >> $GITHUB_ENV
+            fi
+
           fi
-          if [ "${{ matrix.build_type }}" = "full" ]; then
-            echo "CMAKE_EXTRA=-DVIRCADIA_CPU_ARCHITECTURE= -DBUILD_TOOLS:BOOLEAN=FALSE -DHIFI_PYTHON_EXEC:FILEPATH=$(which python3)" >> $GITHUB_ENV
-          else
-            echo "CMAKE_EXTRA=-DVIRCADIA_CPU_ARCHITECTURE= -DCLIENT_ONLY=1 -DBUILD_TOOLS:BOOLEAN=FALSE -DHIFI_PYTHON_EXEC:FILEPATH=$(which python3)" >> $GITHUB_ENV
+
+          if [[ "${{ matrix.os }}" != *"aarch64" ]]; then
+            if [ "${{ matrix.build_type }}" = "full" ]; then
+              echo "CMAKE_EXTRA=-DVIRCADIA_CPU_ARCHITECTURE=-msse3 -DBUILD_TOOLS:BOOLEAN=FALSE -DHIFI_PYTHON_EXEC:FILEPATH=$(which python3)" >> $GITHUB_ENV
+            else
+              echo "CMAKE_EXTRA=-DVIRCADIA_CPU_ARCHITECTURE=-msse3 -DCLIENT_ONLY=1 -DBUILD_TOOLS:BOOLEAN=FALSE -DHIFI_PYTHON_EXEC:FILEPATH=$(which python3)" >> $GITHUB_ENV
+            fi
           fi
         fi
+
         # Mac build variables
         if [ "${{ matrix.os }}" = "macOS-10.15" ]; then
           echo "PYTHON_EXEC=python3" >> $GITHUB_ENV