diff --git a/app/cdash/app/Model/Project.php b/app/cdash/app/Model/Project.php
index 207f940cc8..41b3e33977 100644
--- a/app/cdash/app/Model/Project.php
+++ b/app/cdash/app/Model/Project.php
@@ -30,6 +30,7 @@
 use DateTimeZone;
 use Exception;
 use Illuminate\Database\Eloquent\Collection;
+use Illuminate\Support\Facades\Cache;
 use Illuminate\Support\Facades\DB;
 use Illuminate\Support\Facades\Log;
 use PDO;
@@ -501,6 +502,15 @@ public function CheckForTooManyBuilds(): bool
             return false;
         }
 
+        // Fetching the exact build count is expensive, so don't do it if it's been less than
+        // 10 minutes since the last time we checked.  While this means build counts can temporarily
+        // be higher than the limit, it lightens the database load during peak hours.
+        $cache_key = "check_too_many_builds_project_{$this->Id}";
+        if (Cache::has($cache_key)) {
+            return false;
+        }
+        Cache::put($cache_key, true, 10 * 60);
+
         $project = EloquentProject::findOrFail((int) $this->Id);
         $num_builds = $project->builds()->onlyParents()->count();
 
diff --git a/app/cdash/tests/test_limitedbuilds.php b/app/cdash/tests/test_limitedbuilds.php
index af8eea1551..aba69ded69 100644
--- a/app/cdash/tests/test_limitedbuilds.php
+++ b/app/cdash/tests/test_limitedbuilds.php
@@ -9,6 +9,7 @@
 use CDash\Database;
 use CDash\Model\Build;
 use CDash\Model\Project;
+use Illuminate\Support\Facades\Cache;
 use Illuminate\Support\Facades\DB;
 
 class LimitedBuildsTestCase extends KWWebTestCase
@@ -58,14 +59,21 @@ public function testLimitedBuilds(): void
 
         $project = App\Models\Project::findOrFail((int) $this->Projects[0]->Id);
 
-        // Submit two builds to the 'Limited' project.
-        // The second submission will cause the first build to get deleted.
+        // Submit three builds to the 'Limited' project.
+        // The second submission will not cause the first build to get deleted because it's been
+        // than 10 minutes since the previous build.  Flushing the cache expires the record and
+        // means submitting the 3rd build will cause the first two to be deleted.
         $this->submitBuild(1, 'Limited');
         $this->assertEqual($project->refresh()->builds()->count(), 1);
 
         $this->get_build_stmt->execute([$this->Projects[0]->Id]);
         $buildid1 = $this->get_build_stmt->fetchColumn();
 
+        $this->submitBuild(2, 'Limited');
+        $this->assertEqual($project->refresh()->builds()->count(), 2);
+
+        Cache::flush();
+
         $this->submitBuild(2, 'Limited');
         $this->assertEqual($project->refresh()->builds()->count(), 1);
 
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 5986c258c6..30b41920af 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -9219,6 +9219,12 @@ parameters:
 			count: 1
 			path: app/cdash/app/Model/Project.php
 
+		-
+			rawMessage: 'Method CDash\Model\Project::CheckForTooManyBuilds() throws checked exception Psr\SimpleCache\InvalidArgumentException but it''s missing from the PHPDoc @throws tag.'
+			identifier: missingType.checkedException
+			count: 1
+			path: app/cdash/app/Model/Project.php
+
 		-
 			rawMessage: 'Method CDash\Model\Project::ComputeTestingDayBounds() has parameter $date with no type specified.'
 			identifier: missingType.parameter