diff --git a/frontend-modern/src/components/Dashboard/EnhancedCPUBar.tsx b/frontend-modern/src/components/Dashboard/EnhancedCPUBar.tsx
index fc6e2b6..bcd8bf9 100644
--- a/frontend-modern/src/components/Dashboard/EnhancedCPUBar.tsx
+++ b/frontend-modern/src/components/Dashboard/EnhancedCPUBar.tsx
@@ -82,6 +82,9 @@ export function EnhancedCPUBar(props: EnhancedCPUBarProps) {
                         {/* Label */}
                         <span class="absolute inset-0 flex items-center justify-center text-[10px] font-semibold text-gray-700 dark:text-gray-100 leading-none pointer-events-none">
                             {formatPercent(props.usage)}
+                            <Show when={props.cores}>
+                                <span class="ml-1 text-[9px] font-normal opacity-70">({props.cores}c)</span>
+                            </Show>
                         </span>
                     </div>
 
diff --git a/internal/api/system_settings.go b/internal/api/system_settings.go
index 600470f..ab56443 100644
--- a/internal/api/system_settings.go
+++ b/internal/api/system_settings.go
@@ -294,8 +294,8 @@ func validateSystemSettings(_ *config.SystemSettings, rawRequest map[string]inte
 			if !ok {
 				return fmt.Errorf("discoveryConfig.max_concurrent must be a number")
 			}
-			if value <= 0 || value > 1000 {
-				return fmt.Errorf("discoveryConfig.max_concurrent must be between 1 and 1000")
+			if value <= 0 || value > 1000 || value != float64(int(value)) {
+				return fmt.Errorf("discoveryConfig.max_concurrent must be a whole number between 1 and 1000")
 			}
 		}
 
diff --git a/internal/api/system_settings_validate_test.go b/internal/api/system_settings_validate_test.go
index d84620a..5ce0d36 100644
--- a/internal/api/system_settings_validate_test.go
+++ b/internal/api/system_settings_validate_test.go
@@ -1068,18 +1068,22 @@ func TestValidateSystemSettings_BoundaryConditions(t *testing.T) {
 		{name: "connectionTimeout: 299.999", input: map[string]interface{}{"connectionTimeout": 299.999}, expectError: false},
 		{name: "connectionTimeout: 300.001", input: map[string]interface{}{"connectionTimeout": 300.001}, expectError: true},
 
-		// Max concurrent boundaries
-		// Note: The validation is `value <= 0 || value > 1000`, so 0.999 is actually valid
+		// Max concurrent boundaries - fractional values are rejected since it's a goroutine count
 		{
-			name:        "max_concurrent: 0.999",
+			name:        "max_concurrent: 0.999 fractional rejected",
 			input:       map[string]interface{}{"discoveryConfig": map[string]interface{}{"max_concurrent": 0.999}},
-			expectError: false,
+			expectError: true,
 		},
 		{
-			name:        "max_concurrent: 1000.001",
+			name:        "max_concurrent: 1000.001 fractional rejected",
 			input:       map[string]interface{}{"discoveryConfig": map[string]interface{}{"max_concurrent": 1000.001}},
 			expectError: true,
 		},
+		{
+			name:        "max_concurrent: 5.5 fractional rejected",
+			input:       map[string]interface{}{"discoveryConfig": map[string]interface{}{"max_concurrent": 5.5}},
+			expectError: true,
+		},
 	}
 
 	for _, tt := range tests {