diff --git a/resources/tests/org.eclipse.core.tests.resources/src/org/eclipse/core/tests/internal/builders/ParallelBuildChainTest.java b/resources/tests/org.eclipse.core.tests.resources/src/org/eclipse/core/tests/internal/builders/ParallelBuildChainTest.java
index 0001f00086a..b6415591977 100644
--- a/resources/tests/org.eclipse.core.tests.resources/src/org/eclipse/core/tests/internal/builders/ParallelBuildChainTest.java
+++ b/resources/tests/org.eclipse.core.tests.resources/src/org/eclipse/core/tests/internal/builders/ParallelBuildChainTest.java
@@ -144,7 +144,7 @@ public void testIndividualProjectBuilds_ProjectRelaxedRule() throws Exception {
 
 	@Test
 	public void testIndividualProjectBuilds_WithManyProjects_ProjectRelaxedRule() throws Exception {
-		int numberOfParallelBuilds = 30;
+		int numberOfParallelBuilds = 15;
 		var longRunningProjects = createMultipleTestProjects(numberOfParallelBuilds, BuildDurationType.LONG_RUNNING,
 				RuleType.CURRENT_PROJECT_RELAXED);
 		executeIndividualFullProjectBuilds(numberOfParallelBuilds, () -> {