diff --git a/tools/internal_ci/macos/grpc_basictests.cfg b/tools/internal_ci/macos/grpc_basictests.cfg
index e10c2e36b272baa886282a7624aaa2da75bf8b1b..3faba2fc36ce9c0369f518e8c689f3f5a78c1e79 100644
--- a/tools/internal_ci/macos/grpc_basictests.cfg
+++ b/tools/internal_ci/macos/grpc_basictests.cfg
@@ -27,5 +27,5 @@ action {
 
 env_vars {
   key: "RUN_TESTS_FLAGS"
-  value: "-f basictests macos --internal_ci -j 2 --inner_jobs 4 --bq_result_table aggregate_results"
+  value: "-f basictests macos --internal_ci -j 1 --inner_jobs 4 --bq_result_table aggregate_results"
 }
diff --git a/tools/internal_ci/macos/grpc_basictests_dbg.cfg b/tools/internal_ci/macos/grpc_basictests_dbg.cfg
new file mode 100644
index 0000000000000000000000000000000000000000..53bda1ff0a6ac8e2b8a089415dd1d9e7cbb26128
--- /dev/null
+++ b/tools/internal_ci/macos/grpc_basictests_dbg.cfg
@@ -0,0 +1,31 @@
+# Copyright 2017 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Config file for the internal CI (in protobuf text format)
+
+# Location of the continuous shell script in repository.
+build_file: "grpc/tools/internal_ci/macos/grpc_run_tests_matrix.sh"
+gfile_resources: "/bigstore/grpc-testing-secrets/gcp_credentials/GrpcTesting-d0eeee2db331.json"
+timeout_mins: 240
+action {
+  define_artifacts {
+    regex: "**/*sponge_log.xml"
+    regex: "github/grpc/reports/**"
+  }
+}
+
+env_vars {
+  key: "RUN_TESTS_FLAGS"
+  value: "-f basictests macos dbg --internal_ci -j 1 --inner_jobs 4 --bq_result_table aggregate_results"
+}
diff --git a/tools/internal_ci/macos/grpc_basictests_opt.cfg b/tools/internal_ci/macos/grpc_basictests_opt.cfg
new file mode 100644
index 0000000000000000000000000000000000000000..d359eb601a06a2cd396821948ef2986061fe9487
--- /dev/null
+++ b/tools/internal_ci/macos/grpc_basictests_opt.cfg
@@ -0,0 +1,31 @@
+# Copyright 2017 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Config file for the internal CI (in protobuf text format)
+
+# Location of the continuous shell script in repository.
+build_file: "grpc/tools/internal_ci/macos/grpc_run_tests_matrix.sh"
+gfile_resources: "/bigstore/grpc-testing-secrets/gcp_credentials/GrpcTesting-d0eeee2db331.json"
+timeout_mins: 240
+action {
+  define_artifacts {
+    regex: "**/*sponge_log.xml"
+    regex: "github/grpc/reports/**"
+  }
+}
+
+env_vars {
+  key: "RUN_TESTS_FLAGS"
+  value: "-f basictests macos opt --internal_ci -j 1 --inner_jobs 4 --bq_result_table aggregate_results"
+}
diff --git a/tools/internal_ci/macos/pull_request/grpc_basictests.cfg b/tools/internal_ci/macos/pull_request/grpc_basictests_dbg.cfg
similarity index 93%
rename from tools/internal_ci/macos/pull_request/grpc_basictests.cfg
rename to tools/internal_ci/macos/pull_request/grpc_basictests_dbg.cfg
index e297091560a2326d95c97de578c8cb32e6e58017..f058f0c7e47b1552d5297c0ff82803fe45af68f8 100644
--- a/tools/internal_ci/macos/pull_request/grpc_basictests.cfg
+++ b/tools/internal_ci/macos/pull_request/grpc_basictests_dbg.cfg
@@ -27,5 +27,5 @@ action {
 
 env_vars {
   key: "RUN_TESTS_FLAGS"
-  value: "-f basictests macos --internal_ci -j 2 --inner_jobs 4"
+  value: "-f basictests macos dbg --internal_ci -j 1 --inner_jobs 4"
 }
diff --git a/tools/internal_ci/macos/pull_request/grpc_basictests_opt.cfg b/tools/internal_ci/macos/pull_request/grpc_basictests_opt.cfg
new file mode 100644
index 0000000000000000000000000000000000000000..5048baaf483c35cd1ad13b98d29878d7c015c909
--- /dev/null
+++ b/tools/internal_ci/macos/pull_request/grpc_basictests_opt.cfg
@@ -0,0 +1,31 @@
+# Copyright 2017 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Config file for the internal CI (in protobuf text format)
+
+# Location of the continuous shell script in repository.
+build_file: "grpc/tools/internal_ci/macos/grpc_run_tests_matrix.sh"
+gfile_resources: "/bigstore/grpc-testing-secrets/gcp_credentials/GrpcTesting-d0eeee2db331.json"
+timeout_mins: 240
+action {
+  define_artifacts {
+    regex: "**/*sponge_log.xml"
+    regex: "github/grpc/reports/**"
+  }
+}
+
+env_vars {
+  key: "RUN_TESTS_FLAGS"
+  value: "-f basictests macos opt --internal_ci -j 1 --inner_jobs 4"
+}