diff --git a/master/custom/builders.py b/master/custom/builders.py
index fe1cbe20..02297d86 100644
--- a/master/custom/builders.py
+++ b/master/custom/builders.py
@@ -211,7 +211,7 @@ def generate_builderdefs(tags, entries):
         Windows64PGOTailcallBuild,
         tags={STABLE, TIER_1},
         worker_name="itamaro-win64-srv-22-aws",
-        branches={MAIN_BRANCH, PR_BRANCH},
+        branches=BRANCHES.only_since(3, 15),
     ),
     BuilderDef(
         "AMD64 Windows PGO NoGIL",
@@ -225,7 +225,7 @@ def generate_builderdefs(tags, entries):
         Windows64PGONoGilTailcallBuild,
         tags={STABLE, TIER_1},
         worker_name="itamaro-win64-srv-22-aws",
-        branches={MAIN_BRANCH, PR_BRANCH},
+        branches=BRANCHES.only_since(3, 15),
     ),
 ]))