diff --git a/src/bootstrap/mk/Makefile.in b/src/bootstrap/mk/Makefile.in
index a1f38b9ac147f..a29c96ff78ceb 100644
--- a/src/bootstrap/mk/Makefile.in
+++ b/src/bootstrap/mk/Makefile.in
@@ -97,13 +97,18 @@ tidy:
 prepare:
 	$(Q)$(BOOTSTRAP) build --stage 2 --dry-run
 
+STAGE_2_TEST_SET1 := test --stage 2 --skip=compiler --skip=src
+STAGE_2_TEST_SET2 := test --stage 2 --skip=tests --skip=coverage-map --skip=coverage-run --skip=library --skip=tidyselftest
+
 ## MSVC native builders
 
+# Set of tests that should represent half of the time of the test suite.
+# Used to split tests across multiple CI runners.
 # this intentionally doesn't use `$(BOOTSTRAP)` so we can test the shebang on Windows
 ci-msvc-py:
-	$(Q)$(CFG_SRC_DIR)/x.py test --stage 2 tidy
+	$(Q)$(CFG_SRC_DIR)/x.py $(STAGE_2_TEST_SET1)
 ci-msvc-ps1:
-	$(Q)$(CFG_SRC_DIR)/x.ps1 test --stage 2 --skip tidy
+	$(Q)$(CFG_SRC_DIR)/x.ps1 $(STAGE_2_TEST_SET2)
 ci-msvc: ci-msvc-py ci-msvc-ps1
 
 ## MingW native builders
@@ -112,9 +117,9 @@ ci-msvc: ci-msvc-py ci-msvc-ps1
 # Used to split tests across multiple CI runners.
 # Test both x and bootstrap entrypoints.
 ci-mingw-x:
-	$(Q)$(CFG_SRC_DIR)/x test --stage 2 --skip=compiler --skip=src
+	$(Q)$(CFG_SRC_DIR)/x $(STAGE_2_TEST_SET1)
 ci-mingw-bootstrap:
-	$(Q)$(BOOTSTRAP) test --stage 2 --skip=tests --skip=coverage-map --skip=coverage-run --skip=library --skip=tidyselftest
+	$(Q)$(BOOTSTRAP) $(STAGE_2_TEST_SET2)
 ci-mingw: ci-mingw-x ci-mingw-bootstrap
 
 .PHONY: dist
diff --git a/src/ci/github-actions/jobs.yml b/src/ci/github-actions/jobs.yml
index 6bf4a75d080cc..6c0f43bd4df0d 100644
--- a/src/ci/github-actions/jobs.yml
+++ b/src/ci/github-actions/jobs.yml
@@ -442,11 +442,18 @@ auto:
   #  Windows Builders  #
   ######################
 
-  - name: x86_64-msvc
+  # x86_64-msvc is split into two jobs to run tests in parallel.
+  - name: x86_64-msvc-1
     env:
       RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-msvc --enable-profiler
-      SCRIPT: make ci-msvc
-    <<: *job-windows-8c
+      SCRIPT: make ci-msvc-py
+    <<: *job-windows
+
+  - name: x86_64-msvc-2
+    env:
+      RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-msvc --enable-profiler
+      SCRIPT: make ci-msvc-ps1
+    <<: *job-windows
 
   - name: i686-msvc
     env: