diff --git a/.github/workflows/studio-windows-api-smoke.yml b/.github/workflows/studio-windows-api-smoke.yml
index 0208b0f5d..b166112c4 100644
--- a/.github/workflows/studio-windows-api-smoke.yml
+++ b/.github/workflows/studio-windows-api-smoke.yml
@@ -78,6 +78,30 @@ jobs:
           HF_HUB_ENABLE_HF_TRANSFER=1 \
             hf download "$GGUF_REPO" "$GGUF_FILE"
 
+      # Caches around install.ps1 -- restore the heavy artefacts the
+      # installer would otherwise rebuild from scratch every run.
+      # Keys hash every input file that would meaningfully change
+      # the produced artefact, so a stale cache cannot mask a real
+      # dependency change.
+      - name: Cache Studio venv (~/.unsloth/studio/unsloth_studio)
+        id: cache-studio-venv
+        uses: actions/cache@v4
+        with:
+          path: ~/.unsloth/studio/unsloth_studio
+          key: ${{ runner.os }}-studio-venv-v1-${{ hashFiles('pyproject.toml', 'studio/backend/requirements/**', 'install.ps1', 'studio/setup.ps1', 'studio/install_python_stack.py') }}
+      - name: Cache prebuilt llama.cpp (~/.unsloth/llama.cpp)
+        id: cache-llama-prebuilt
+        uses: actions/cache@v4
+        with:
+          path: ~/.unsloth/llama.cpp
+          key: ${{ runner.os }}-llama-cpp-prebuilt-v1-${{ hashFiles('studio/install_llama_prebuilt.py') }}
+      - name: Cache frontend dist (studio/frontend/dist)
+        id: cache-frontend-dist
+        uses: actions/cache@v4
+        with:
+          path: studio/frontend/dist
+          key: ${{ runner.os }}-studio-frontend-dist-v1-${{ hashFiles('studio/frontend/package-lock.json', 'studio/frontend/src/**', 'studio/frontend/index.html', 'studio/frontend/vite.config.*', 'studio/frontend/tsconfig*.json', 'studio/frontend/components.json') }}
+
       - name: Install Studio (--local, --no-torch)
         shell: pwsh
         env:
diff --git a/.github/workflows/studio-windows-inference-smoke.yml b/.github/workflows/studio-windows-inference-smoke.yml
index 32a86d239..454c21c75 100644
--- a/.github/workflows/studio-windows-inference-smoke.yml
+++ b/.github/workflows/studio-windows-inference-smoke.yml
@@ -88,6 +88,30 @@ jobs:
           HF_HUB_ENABLE_HF_TRANSFER=1 \
             hf download "$GGUF_REPO" "$GGUF_FILE"
 
+      # Caches around install.ps1 -- restore the heavy artefacts the
+      # installer would otherwise rebuild from scratch every run.
+      # Keys hash every input file that would meaningfully change
+      # the produced artefact, so a stale cache cannot mask a real
+      # dependency change.
+      - name: Cache Studio venv (~/.unsloth/studio/unsloth_studio)
+        id: cache-studio-venv
+        uses: actions/cache@v4
+        with:
+          path: ~/.unsloth/studio/unsloth_studio
+          key: ${{ runner.os }}-studio-venv-v1-${{ hashFiles('pyproject.toml', 'studio/backend/requirements/**', 'install.ps1', 'studio/setup.ps1', 'studio/install_python_stack.py') }}
+      - name: Cache prebuilt llama.cpp (~/.unsloth/llama.cpp)
+        id: cache-llama-prebuilt
+        uses: actions/cache@v4
+        with:
+          path: ~/.unsloth/llama.cpp
+          key: ${{ runner.os }}-llama-cpp-prebuilt-v1-${{ hashFiles('studio/install_llama_prebuilt.py') }}
+      - name: Cache frontend dist (studio/frontend/dist)
+        id: cache-frontend-dist
+        uses: actions/cache@v4
+        with:
+          path: studio/frontend/dist
+          key: ${{ runner.os }}-studio-frontend-dist-v1-${{ hashFiles('studio/frontend/package-lock.json', 'studio/frontend/src/**', 'studio/frontend/index.html', 'studio/frontend/vite.config.*', 'studio/frontend/tsconfig*.json', 'studio/frontend/components.json') }}
+
       - name: Install Studio (--local, --no-torch)
         shell: pwsh
         env:
@@ -353,6 +377,30 @@ jobs:
           HF_HUB_ENABLE_HF_TRANSFER=1 \
             hf download "$GGUF_REPO" "$GGUF_FILE"
 
+      # Caches around install.ps1 -- restore the heavy artefacts the
+      # installer would otherwise rebuild from scratch every run.
+      # Keys hash every input file that would meaningfully change
+      # the produced artefact, so a stale cache cannot mask a real
+      # dependency change.
+      - name: Cache Studio venv (~/.unsloth/studio/unsloth_studio)
+        id: cache-studio-venv
+        uses: actions/cache@v4
+        with:
+          path: ~/.unsloth/studio/unsloth_studio
+          key: ${{ runner.os }}-studio-venv-v1-${{ hashFiles('pyproject.toml', 'studio/backend/requirements/**', 'install.ps1', 'studio/setup.ps1', 'studio/install_python_stack.py') }}
+      - name: Cache prebuilt llama.cpp (~/.unsloth/llama.cpp)
+        id: cache-llama-prebuilt
+        uses: actions/cache@v4
+        with:
+          path: ~/.unsloth/llama.cpp
+          key: ${{ runner.os }}-llama-cpp-prebuilt-v1-${{ hashFiles('studio/install_llama_prebuilt.py') }}
+      - name: Cache frontend dist (studio/frontend/dist)
+        id: cache-frontend-dist
+        uses: actions/cache@v4
+        with:
+          path: studio/frontend/dist
+          key: ${{ runner.os }}-studio-frontend-dist-v1-${{ hashFiles('studio/frontend/package-lock.json', 'studio/frontend/src/**', 'studio/frontend/index.html', 'studio/frontend/vite.config.*', 'studio/frontend/tsconfig*.json', 'studio/frontend/components.json') }}
+
       - name: Install Studio (--local, --no-torch)
         shell: pwsh
         env:
@@ -709,6 +757,30 @@ jobs:
           HF_HUB_ENABLE_HF_TRANSFER=1 \
             hf download "$GGUF_REPO" "$MMPROJ_FILE"
 
+      # Caches around install.ps1 -- restore the heavy artefacts the
+      # installer would otherwise rebuild from scratch every run.
+      # Keys hash every input file that would meaningfully change
+      # the produced artefact, so a stale cache cannot mask a real
+      # dependency change.
+      - name: Cache Studio venv (~/.unsloth/studio/unsloth_studio)
+        id: cache-studio-venv
+        uses: actions/cache@v4
+        with:
+          path: ~/.unsloth/studio/unsloth_studio
+          key: ${{ runner.os }}-studio-venv-v1-${{ hashFiles('pyproject.toml', 'studio/backend/requirements/**', 'install.ps1', 'studio/setup.ps1', 'studio/install_python_stack.py') }}
+      - name: Cache prebuilt llama.cpp (~/.unsloth/llama.cpp)
+        id: cache-llama-prebuilt
+        uses: actions/cache@v4
+        with:
+          path: ~/.unsloth/llama.cpp
+          key: ${{ runner.os }}-llama-cpp-prebuilt-v1-${{ hashFiles('studio/install_llama_prebuilt.py') }}
+      - name: Cache frontend dist (studio/frontend/dist)
+        id: cache-frontend-dist
+        uses: actions/cache@v4
+        with:
+          path: studio/frontend/dist
+          key: ${{ runner.os }}-studio-frontend-dist-v1-${{ hashFiles('studio/frontend/package-lock.json', 'studio/frontend/src/**', 'studio/frontend/index.html', 'studio/frontend/vite.config.*', 'studio/frontend/tsconfig*.json', 'studio/frontend/components.json') }}
+
       - name: Install Studio (--local, --no-torch)
         shell: pwsh
         env:
diff --git a/.github/workflows/studio-windows-ui-smoke.yml b/.github/workflows/studio-windows-ui-smoke.yml
index 2ceb99fa0..03255de3b 100644
--- a/.github/workflows/studio-windows-ui-smoke.yml
+++ b/.github/workflows/studio-windows-ui-smoke.yml
@@ -87,6 +87,31 @@ jobs:
           HF_HUB_ENABLE_HF_TRANSFER=1 \
             hf download "$GGUF_REPO" "$GGUF_FILE"
 
+      # Caches around install.ps1 -- restore the heavy artefacts the
+      # installer would otherwise rebuild from scratch every run.
+      # Keys hash on every input file that would meaningfully change
+      # the produced artefact, so a stale cache cannot mask a real
+      # dependency change. Cache scope is branch-partitioned by
+      # GitHub Actions, so a malicious PR can't poison main's cache.
+      - name: Cache Studio venv (~/.unsloth/studio/unsloth_studio)
+        id: cache-studio-venv
+        uses: actions/cache@v4
+        with:
+          path: ~/.unsloth/studio/unsloth_studio
+          key: ${{ runner.os }}-studio-venv-v1-${{ hashFiles('pyproject.toml', 'studio/backend/requirements/**', 'install.ps1', 'studio/setup.ps1', 'studio/install_python_stack.py') }}
+      - name: Cache prebuilt llama.cpp (~/.unsloth/llama.cpp)
+        id: cache-llama-prebuilt
+        uses: actions/cache@v4
+        with:
+          path: ~/.unsloth/llama.cpp
+          key: ${{ runner.os }}-llama-cpp-prebuilt-v1-${{ hashFiles('studio/install_llama_prebuilt.py') }}
+      - name: Cache frontend dist (studio/frontend/dist)
+        id: cache-frontend-dist
+        uses: actions/cache@v4
+        with:
+          path: studio/frontend/dist
+          key: ${{ runner.os }}-studio-frontend-dist-v1-${{ hashFiles('studio/frontend/package-lock.json', 'studio/frontend/src/**', 'studio/frontend/index.html', 'studio/frontend/vite.config.*', 'studio/frontend/tsconfig*.json', 'studio/frontend/components.json') }}
+
       - name: Install Studio (--local, --no-torch)
         # install.ps1 is the supported Windows installer. install.sh
         # has no Windows branch (apt-get / brew calls). The PS1
diff --git a/.github/workflows/studio-windows-update-smoke.yml b/.github/workflows/studio-windows-update-smoke.yml
index 86957f2b3..e2bf771dd 100644
--- a/.github/workflows/studio-windows-update-smoke.yml
+++ b/.github/workflows/studio-windows-update-smoke.yml
@@ -73,6 +73,30 @@ jobs:
           # then fatal-errors with "Cache folder path is retrieved
           # for pip but doesn't exist on disk".
 
+      # Caches around install.ps1 -- restore the heavy artefacts the
+      # installer would otherwise rebuild from scratch every run.
+      # Keys hash every input file that would meaningfully change
+      # the produced artefact, so a stale cache cannot mask a real
+      # dependency change.
+      - name: Cache Studio venv (~/.unsloth/studio/unsloth_studio)
+        id: cache-studio-venv
+        uses: actions/cache@v4
+        with:
+          path: ~/.unsloth/studio/unsloth_studio
+          key: ${{ runner.os }}-studio-venv-v1-${{ hashFiles('pyproject.toml', 'studio/backend/requirements/**', 'install.ps1', 'studio/setup.ps1', 'studio/install_python_stack.py') }}
+      - name: Cache prebuilt llama.cpp (~/.unsloth/llama.cpp)
+        id: cache-llama-prebuilt
+        uses: actions/cache@v4
+        with:
+          path: ~/.unsloth/llama.cpp
+          key: ${{ runner.os }}-llama-cpp-prebuilt-v1-${{ hashFiles('studio/install_llama_prebuilt.py') }}
+      - name: Cache frontend dist (studio/frontend/dist)
+        id: cache-frontend-dist
+        uses: actions/cache@v4
+        with:
+          path: studio/frontend/dist
+          key: ${{ runner.os }}-studio-frontend-dist-v1-${{ hashFiles('studio/frontend/package-lock.json', 'studio/frontend/src/**', 'studio/frontend/index.html', 'studio/frontend/vite.config.*', 'studio/frontend/tsconfig*.json', 'studio/frontend/components.json') }}
+
       - name: Install Studio (--local, --no-torch)
         shell: pwsh
         env: