diff --git a/.github/workflows/precommit.yml b/.github/workflows/precommit.yml
index 9b31ac9d4a..6beba49a74 100644
--- a/.github/workflows/precommit.yml
+++ b/.github/workflows/precommit.yml
@@ -136,6 +136,10 @@ jobs:
           - python-version: "3.14"
             cloud-provider: gcp
             os: windows-latest-64-cores
+            # Cap pytest-xdist parallelism — Python 3.14 + Windows 64-core runners
+            # exhaust threads/memory at -n logical (MemoryError in pytest_timeout
+            # Timer.start, plus stack overflows in connector ThreadPoolExecutors).
+            tox-extra-factors: "-lowparallel"
     steps:
       - name: Checkout Code
         uses: actions/checkout@v4
@@ -189,12 +193,13 @@ jobs:
       # do not run other tests for macos
       - if: ${{ matrix.os != 'macos-latest' }}
         name: Run tests (excluding doctests)
-        run: python -m tox -e "py${PYTHON_VERSION/\./}-notdoctest-ci"
+        run: python -m tox -e "py${PYTHON_VERSION/\./}-notdoctest${EXTRA_TOX_FACTORS}-ci"
         env:
           PYTHON_VERSION: ${{ matrix.python-version }}
           cloud_provider: ${{ matrix.cloud-provider }}
           PYTEST_ADDOPTS: --color=yes --tb=short
           TOX_PARALLEL_NO_SPINNER: 1
+          EXTRA_TOX_FACTORS: ${{ matrix.tox-extra-factors }}
           SNOWPARK_PYTHON_API_TEST_BUCKET_PATH: ${{ secrets.SNOWPARK_PYTHON_API_TEST_BUCKET_PATH }}
           SNOWPARK_PYTHON_API_S3_STORAGE_INTEGRATION: ${{ vars.SNOWPARK_PYTHON_API_S3_STORAGE_INTEGRATION }}
         shell: bash
diff --git a/tox.ini b/tox.ini
index fec74cd6a1..9b4ab73404 100644
--- a/tox.ini
+++ b/tox.ini
@@ -73,8 +73,12 @@ setenv =
     # For AST tests, use just 36 cores, because using more cores sometimes
     # causes the test job to fail with exit code 143, which supposedly means
     # that it uses too many machine resources.
-    !doctest-!ast: SNOWFLAKE_PYTEST_PARALLELISM = -n logical
+    !doctest-!ast-!lowparallel: SNOWFLAKE_PYTEST_PARALLELISM = -n logical
     ast: SNOWFLAKE_PYTEST_PARALLELISM = -n 36
+    # Python 3.14 + Windows 64-core runners hit MemoryError in pytest_timeout's
+    # Timer.start() and thread-pool stack overflows when running 64 xdist workers,
+    # so cap parallelism the same way ast tests do.
+    lowparallel: SNOWFLAKE_PYTEST_PARALLELISM = -n 36
     # Snowpark uses 4 workers for daily testing since some of its test jobs use weak MacOS instances.
     !doctest: SNOWFLAKE_PYTEST_DAILY_PARALLELISM = -n 6
     # Set test type, either notset, unit, integ, or both