diff --git a/app/Models/Server.php b/app/Models/Server.php
index c4efe832b..fd1ce3e69 100644
--- a/app/Models/Server.php
+++ b/app/Models/Server.php
@@ -691,7 +691,7 @@ public function getCpuMetrics(int $mins = 5)
                 $metrics = $this->downsampleLTTB($metrics, 1000);
             }
 
-            return $metrics;
+            return collect($metrics);
         }
     }
 
@@ -720,7 +720,7 @@ public function getMemoryMetrics(int $mins = 5)
                 $metrics = $this->downsampleLTTB($metrics, 1000);
             }
 
-            return $metrics;
+            return collect($metrics);
         }
     }
 
@@ -736,6 +736,8 @@ private function downsampleLTTB(array $data, int $threshold): array
     {
         $dataLength = count($data);
 
+        // Return unchanged if threshold >= data length, or if threshold <= 2
+        // (threshold <= 2 would cause division by zero in bucket calculation)
         if ($threshold >= $dataLength || $threshold <= 2) {
             return $data;
         }
diff --git a/tests/Unit/ServerMetricsDownsamplingTest.php b/tests/Unit/ServerMetricsDownsamplingTest.php
index cb512289f..819eecc4c 100644
--- a/tests/Unit/ServerMetricsDownsamplingTest.php
+++ b/tests/Unit/ServerMetricsDownsamplingTest.php
@@ -1,75 +1,17 @@
 <?php
 
+use App\Models\Server;
+
 /**
- * LTTB (Largest-Triangle-Three-Buckets) algorithm implementation for testing.
- * This mirrors the implementation in App\Models\Server::downsampleLTTB()
+ * Helper to call the private downsampleLTTB method on Server model via reflection.
  */
-function downsampleLTTB(array $data, int $threshold): array
+function callDownsampleLTTB(array $data, int $threshold): array
 {
-    $dataLength = count($data);
+    $server = new Server;
+    $reflection = new ReflectionClass($server);
+    $method = $reflection->getMethod('downsampleLTTB');
 
-    if ($threshold >= $dataLength || $threshold <= 2) {
-        return $data;
-    }
-
-    $sampled = [];
-    $sampled[] = $data[0]; // Always keep first point
-
-    $bucketSize = ($dataLength - 2) / ($threshold - 2);
-
-    $a = 0; // Index of previous selected point
-
-    for ($i = 0; $i < $threshold - 2; $i++) {
-        // Calculate bucket range
-        $bucketStart = (int) floor(($i + 1) * $bucketSize) + 1;
-        $bucketEnd = (int) floor(($i + 2) * $bucketSize) + 1;
-        $bucketEnd = min($bucketEnd, $dataLength - 1);
-
-        // Calculate average point for next bucket (used as reference)
-        $nextBucketStart = (int) floor(($i + 2) * $bucketSize) + 1;
-        $nextBucketEnd = (int) floor(($i + 3) * $bucketSize) + 1;
-        $nextBucketEnd = min($nextBucketEnd, $dataLength - 1);
-
-        $avgX = 0;
-        $avgY = 0;
-        $nextBucketCount = $nextBucketEnd - $nextBucketStart + 1;
-
-        if ($nextBucketCount > 0) {
-            for ($j = $nextBucketStart; $j <= $nextBucketEnd; $j++) {
-                $avgX += $data[$j][0];
-                $avgY += $data[$j][1];
-            }
-            $avgX /= $nextBucketCount;
-            $avgY /= $nextBucketCount;
-        }
-
-        // Find point in current bucket with largest triangle area
-        $maxArea = -1;
-        $maxAreaIndex = $bucketStart;
-
-        $pointAX = $data[$a][0];
-        $pointAY = $data[$a][1];
-
-        for ($j = $bucketStart; $j <= $bucketEnd; $j++) {
-            // Triangle area calculation
-            $area = abs(
-                ($pointAX - $avgX) * ($data[$j][1] - $pointAY) -
-                ($pointAX - $data[$j][0]) * ($avgY - $pointAY)
-            ) * 0.5;
-
-            if ($area > $maxArea) {
-                $maxArea = $area;
-                $maxAreaIndex = $j;
-            }
-        }
-
-        $sampled[] = $data[$maxAreaIndex];
-        $a = $maxAreaIndex;
-    }
-
-    $sampled[] = $data[$dataLength - 1]; // Always keep last point
-
-    return $sampled;
+    return $method->invoke($server, $data, $threshold);
 }
 
 it('returns data unchanged when below threshold', function () {
@@ -79,7 +21,7 @@ function downsampleLTTB(array $data, int $threshold): array
         [3000, 15.7],
     ];
 
-    $result = downsampleLTTB($data, 1000);
+    $result = callDownsampleLTTB($data, 1000);
 
     expect($result)->toBe($data);
 });
@@ -93,21 +35,24 @@ function downsampleLTTB(array $data, int $threshold): array
         [5000, 12.0],
     ];
 
-    $result = downsampleLTTB($data, 2);
+    $result = callDownsampleLTTB($data, 2);
     expect($result)->toBe($data);
 
-    $result = downsampleLTTB($data, 1);
+    $result = callDownsampleLTTB($data, 1);
     expect($result)->toBe($data);
 });
 
 it('downsamples to target threshold count', function () {
+    // Seed for reproducibility
+    mt_srand(42);
+
     // Generate 100 data points
     $data = [];
     for ($i = 0; $i < 100; $i++) {
-        $data[] = [$i * 1000, rand(0, 100) / 10];
+        $data[] = [$i * 1000, mt_rand(0, 100) / 10];
     }
 
-    $result = downsampleLTTB($data, 10);
+    $result = callDownsampleLTTB($data, 10);
 
     expect(count($result))->toBe(10);
 });
@@ -118,7 +63,7 @@ function downsampleLTTB(array $data, int $threshold): array
         $data[] = [$i * 1000, $i * 1.5];
     }
 
-    $result = downsampleLTTB($data, 20);
+    $result = callDownsampleLTTB($data, 20);
 
     // First point should be preserved
     expect($result[0])->toBe($data[0]);
@@ -133,7 +78,7 @@ function downsampleLTTB(array $data, int $threshold): array
         $data[] = [$i * 60000, sin($i / 10) * 50 + 50]; // Sine wave pattern
     }
 
-    $result = downsampleLTTB($data, 50);
+    $result = callDownsampleLTTB($data, 50);
 
     // Verify all timestamps are in non-decreasing order
     $previousTimestamp = -1;
@@ -144,15 +89,18 @@ function downsampleLTTB(array $data, int $threshold): array
 });
 
 it('handles large datasets efficiently', function () {
+    // Seed for reproducibility
+    mt_srand(123);
+
     // Simulate 30 days of data at 5-second intervals (518,400 points)
     // For test purposes, use 10,000 points
     $data = [];
     for ($i = 0; $i < 10000; $i++) {
-        $data[] = [$i * 5000, rand(0, 100)];
+        $data[] = [$i * 5000, mt_rand(0, 100)];
     }
 
     $startTime = microtime(true);
-    $result = downsampleLTTB($data, 1000);
+    $result = callDownsampleLTTB($data, 1000);
     $executionTime = microtime(true) - $startTime;
 
     expect(count($result))->toBe(1000);
@@ -173,7 +121,7 @@ function downsampleLTTB(array $data, int $threshold): array
         $data[] = [$i * 1000, $value];
     }
 
-    $result = downsampleLTTB($data, 20);
+    $result = callDownsampleLTTB($data, 20);
 
     // The peak (100) and valley (0) should be preserved due to LTTB algorithm
     $values = array_column($result, 1);