diff --git a/sched/irq/irq_dispatch.c b/sched/irq/irq_dispatch.c
index 7a6c8711f6..a2afbb48c5 100644
--- a/sched/irq/irq_dispatch.c
+++ b/sched/irq/irq_dispatch.c
@@ -39,6 +39,12 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+#ifdef CONFIG_ARCH_MINIMAL_VECTORTABLE
+#  define NUSER_IRQS CONFIG_ARCH_NUSER_INTERRUPTS
+#else
+#  define NUSER_IRQS NR_IRQS
+#endif
+
 /* INCR_COUNT - Increment the count of interrupts taken on this IRQ number */
 
 #ifndef CONFIG_SCHED_IRQMONITOR
@@ -81,9 +87,13 @@
          vector(irq, context, arg); \
          elapsed = up_perf_gettime() - start; \
          up_perf_convert(elapsed, &delta); \
-         if (delta.tv_nsec > g_irqvector[ndx].time) \
+         if (ndx < NUSER_IRQS) \
            { \
-             g_irqvector[ndx].time = delta.tv_nsec; \
+             INCR_COUNT(ndx); \
+             if (delta.tv_nsec > g_irqvector[ndx].time) \
+               { \
+                 g_irqvector[ndx].time = delta.tv_nsec; \
+               } \
            } \
          if (CONFIG_SCHED_CRITMONITOR_MAXTIME_IRQ > 0 && \
              elapsed > CONFIG_SCHED_CRITMONITOR_MAXTIME_IRQ) \
@@ -130,8 +140,6 @@ void irq_dispatch(int irq, FAR void *context)
               vector = g_irqvector[ndx].handler;
               arg    = g_irqvector[ndx].arg;
             }
-
-          INCR_COUNT(ndx);
         }
 #else
       if (g_irqvector[ndx].handler)
@@ -139,8 +147,6 @@ void irq_dispatch(int irq, FAR void *context)
           vector = g_irqvector[ndx].handler;
           arg    = g_irqvector[ndx].arg;
         }
-
-      INCR_COUNT(ndx);
 #endif
     }
 #endif