diff --git a/audit/internal/webui/pages.go b/audit/internal/webui/pages.go
index 51b5602..7c9467a 100644
--- a/audit/internal/webui/pages.go
+++ b/audit/internal/webui/pages.go
@@ -1085,6 +1085,12 @@ func renderValidate(opts HandlerOptions) string {
       <p style="color:var(--muted);font-size:13px">Loading NVIDIA GPUs...</p>
     </div>
     <p id="sat-gpu-selection-note" style="font-size:12px;color:var(--muted);margin:10px 0 0">Select at least one NVIDIA GPU to enable NVIDIA validate tasks.</p>
+    <div style="margin-top:10px;padding-top:10px;border-top:1px solid var(--border)">
+      <label class="sat-gpu-row" title="When checked, multi-GPU tests (PSU Pulse, NCCL, NVBandwidth) run on ALL GPUs in the system regardless of the selection above.">
+        <input type="checkbox" id="sat-multi-gpu-all" checked onchange="satUpdateGPUSelectionNote()">
+        <span><strong>Multi-GPU tests</strong> — use all GPUs <span style="font-size:11px;color:var(--muted)">(PSU Pulse, NCCL, NVBandwidth)</span></span>
+      </label>
+    </div>
   </div>
 </div>
 
@@ -1203,6 +1209,10 @@ function satSelectedGPUIndices() {
     .filter(function(v) { return !Number.isNaN(v); })
     .sort(function(a, b) { return a - b; });
 }
+function satMultiGPUAll() {
+  const cb = document.getElementById('sat-multi-gpu-all');
+  return cb ? cb.checked : true;
+}
 function satUpdateGPUSelectionNote() {
   const note = document.getElementById('sat-gpu-selection-note');
   if (!note) return;
@@ -1211,7 +1221,8 @@ function satUpdateGPUSelectionNote() {
     note.textContent = 'Select at least one NVIDIA GPU to enable NVIDIA validate tasks.';
     return;
   }
-  note.textContent = 'Selected NVIDIA GPUs: ' + selected.join(', ') + '.';
+  const multiAll = satMultiGPUAll();
+  note.textContent = 'Selected GPUs: ' + selected.join(', ') + '. Multi-GPU tests: ' + (multiAll ? 'all GPUs in system' : 'selected GPUs only') + '.';
 }
 function satRenderGPUList(gpus) {
   const root = document.getElementById('sat-gpu-list');
@@ -1324,14 +1335,23 @@ function runSATWithOverrides(target, overrides) {
 const nvidiaPerGPUTargets = ['nvidia', 'nvidia-targeted-stress', 'nvidia-targeted-power'];
 // pulse_test and fabric tests run on all selected GPUs simultaneously
 const nvidiaAllGPUTargets = ['nvidia-pulse', 'nvidia-interconnect', 'nvidia-bandwidth'];
+function satAllGPUIndicesForMulti() {
+  // If "Multi-GPU tests — all GPUs" is checked, return all detected GPUs.
+  // Otherwise fall back to the per-GPU selection.
+  if (satMultiGPUAll()) {
+    return loadSatNvidiaGPUs().then(function(gpus) {
+      return gpus.map(function(g) { return Number(g.index); });
+    });
+  }
+  const sel = satSelectedGPUIndices();
+  return Promise.resolve(sel);
+}
 function expandSATTarget(target) {
   if (nvidiaAllGPUTargets.indexOf(target) >= 0) {
-    const selected = satSelectedGPUIndices();
-    if (!selected.length) return Promise.reject(new Error('Select at least one NVIDIA GPU.'));
-    return Promise.resolve([{
-      target: target,
-      overrides: {gpu_indices: selected, display_name: satLabels()[target] || target}
-    }]);
+    return satAllGPUIndicesForMulti().then(function(indices) {
+      if (!indices.length) return Promise.reject(new Error('No NVIDIA GPUs available.'));
+      return [{target: target, overrides: {gpu_indices: indices, display_name: satLabels()[target] || target}}];
+    });
   }
   if (nvidiaPerGPUTargets.indexOf(target) < 0) {
     return Promise.resolve([{target: target}]);
@@ -1350,12 +1370,10 @@ function expandSATTarget(target) {
   })));
 }
 function runNvidiaFabricValidate(target) {
-  const selected = satSelectedGPUIndices();
-  if (!selected.length) {
-    alert('Select at least one NVIDIA GPU.');
-    return;
-  }
-  return runSATWithOverrides(target, {gpu_indices: selected, display_name: satLabels()[target] || target});
+  satAllGPUIndicesForMulti().then(function(indices) {
+    if (!indices.length) { alert('No NVIDIA GPUs available.'); return; }
+    runSATWithOverrides(target, {gpu_indices: indices, display_name: satLabels()[target] || target});
+  });
 }
 function runNvidiaValidateSet(target) {
   return loadSatNvidiaGPUs().then(gpus => {