--- a/taskcluster/ci/test/tests.yml
+++ b/taskcluster/ci/test/tests.yml
@@ -476,16 +476,17 @@ mochitest:
         by-test-platform:
             linux.*-stylo.*: ['autoland', 'mozilla-central', 'try']
             macosx64-stylo.*: ['mozilla-central', 'try']
             windows7-32-stylo.*: ['autoland', 'mozilla-central', 'try']
             default: built-projects
     tier:
         by-test-platform:
             windows10-64-asan.*: 3
+            windows10-64/opt: 3
             default: default
     mozharness:
         by-test-platform:
             android.*:
                 mochitest-flavor: plain
                 script: android_emulator_unittest.py
                 no-read-buildbot-config: true
                 config: