diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 0f1c30822..b7935803d 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -264,6 +264,19 @@ double DivEngine::benchmarkSeek() {
   return tAvg;
 }
 
+double DivEngine::benchmarkWalk() {
+  std::chrono::high_resolution_clock::time_point timeStart=std::chrono::high_resolution_clock::now();
+
+  // benchmark
+  calcSongTimestamps();
+
+  std::chrono::high_resolution_clock::time_point timeEnd=std::chrono::high_resolution_clock::now();
+
+  double t=(double)(std::chrono::duration_cast<std::chrono::microseconds>(timeEnd-timeStart).count())/1000000.0;
+  printf("[RESULT] %fs\n",t);
+  return t;
+}
+
 void DivEngine::notifyInsChange(int ins) {
   BUSY_BEGIN;
   for (int i=0; i<song.systemLen; i++) {
diff --git a/src/engine/engine.h b/src/engine/engine.h
index 21414afbc..71842de23 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -821,6 +821,7 @@ class DivEngine {
     // benchmark (returns time in seconds)
     double benchmarkPlayback();
     double benchmarkSeek();
+    double benchmarkWalk();
 
     // returns the minimum VGM version which may carry the specified system, or 0 if none.
     int minVGMVersion(DivSystem which);
diff --git a/src/engine/song.cpp b/src/engine/song.cpp
index 116815da7..77ccbf052 100644
--- a/src/engine/song.cpp
+++ b/src/engine/song.cpp
@@ -19,6 +19,7 @@
 
 #include "song.h"
 #include "../ta-log.h"
+#include <inttypes.h>
 #include <chrono>
 
 TimeMicros DivSongTimestamps::getTimes(int order, int row) {
@@ -347,22 +348,40 @@ void DivSubSong::calcTimestamps(int chans, std::vector<DivGroovePattern>& groove
 
   // MAKE IT WORK
   while (!endOfSong) {
+    // heuristic
+    int advance=(curVirtualTempoD*ticks)/curVirtualTempoN;
+    for (int i=0; i<chans; i++) {
+      if (rowDelay[i]>0) {
+        if (rowDelay[i]<advance) advance=rowDelay[i];
+      }
+    }
+    if (advance<1) advance=1;
+
+    //logV("tick %" PRIu64 " advance: %d",ts.totalTicks,advance);
+
     // cycle channels to find a tick rate/tempo change effect after delay
     // (unfortunately Cxxx and F0xx are not pre-effects and obey EDxx)
     for (int i=0; i<chans; i++) {
       if (rowDelay[i]>0) {
-        if (--rowDelay[i]==0) {
+        rowDelay[i]-=advance;
+        if (rowDelay[i]==0) {
           tinyProcessRow(i,true);
         }
       }
     }
 
     // run virtual tempo
-    tempoAccum+=curVirtualTempoN;
+    tempoAccum+=curVirtualTempoN*advance;
     while (tempoAccum>=curVirtualTempoD) {
-      tempoAccum-=curVirtualTempoD;
+      int ticksToRun=tempoAccum/curVirtualTempoD;
+      tempoAccum%=curVirtualTempoD;
       // tick counter
-      if (--ticks<=0) {
+      ticks-=ticksToRun;
+      if (ticks<0) {
+        // if ticks is negative, we must call ticks back
+        tempoAccum+=-ticks*curVirtualTempoD;
+      }
+      if (ticks<=0) {
         if (shallStopSched) {
           shallStop=true;
           break;
@@ -400,8 +419,8 @@ void DivSubSong::calcTimestamps(int chans, std::vector<DivGroovePattern>& groove
 
     if (!endOfSong) {
       // update playback time
-      double dt=divider;//*((double)virtualTempoN/(double)MAX(1,virtualTempoD));
-      ts.totalTicks++;
+      double dt=divider/(double)advance;//*((double)virtualTempoN/(double)MAX(1,virtualTempoD));
+      ts.totalTicks+=advance;
 
       ts.totalTime.micros+=1000000/dt;
       totalMicrosOff+=fmod(1000000.0,dt);
@@ -410,9 +429,10 @@ void DivSubSong::calcTimestamps(int chans, std::vector<DivGroovePattern>& groove
         ts.totalTime.micros++;
       }
       if (ts.totalTime.micros>=1000000) {
-        ts.totalTime.micros-=1000000;
         // who's gonna play a song for 68 years?
-        if (ts.totalTime.seconds<0x7fffffff) ts.totalTime.seconds++;
+        ts.totalTime.seconds+=ts.totalTime.micros/1000000;
+        if (ts.totalTime.seconds<0) ts.totalTime.seconds=INT_MAX;
+        ts.totalTime.micros%=1000000;
       }
     }
     if (ts.maxRow[curOrder]<curRow) ts.maxRow[curOrder]=curRow;
@@ -425,6 +445,7 @@ void DivSubSong::calcTimestamps(int chans, std::vector<DivGroovePattern>& groove
 
   std::chrono::high_resolution_clock::time_point timeEnd=std::chrono::high_resolution_clock::now();
   logV("calcTimestamps() took %dµs",std::chrono::duration_cast<std::chrono::microseconds>(timeEnd-timeStart).count());
+  logV("song length: %s; %" PRIu64 " ticks",ts.totalTime.toString(6,TA_TIME_FORMAT_AUTO),ts.totalTicks);
 }
 
 void DivSubSong::clearData() {
diff --git a/src/engine/song.h b/src/engine/song.h
index 437e1159e..4b6e1b7fc 100644
--- a/src/engine/song.h
+++ b/src/engine/song.h
@@ -171,7 +171,7 @@ struct DivGroovePattern {
 struct DivSongTimestamps {
   // song duration (in seconds and microseconds)
   TimeMicros totalTime;
-  int totalTicks;
+  uint64_t totalTicks;
   int totalRows;
 
   // loop region (order/row positions)
diff --git a/src/gui/debugWindow.cpp b/src/gui/debugWindow.cpp
index 1b3ba9259..dfd809e84 100644
--- a/src/gui/debugWindow.cpp
+++ b/src/gui/debugWindow.cpp
@@ -21,7 +21,7 @@
 #include "guiConst.h"
 #include "debug.h"
 #include "IconsFontAwesome4.h"
-#include <SDL_timer.h>
+#include <inttypes.h>
 #include <fmt/printf.h>
 #include "imgui.h"
 #include "imgui_internal.h"
@@ -208,7 +208,7 @@ void FurnaceGUI::drawDebug() {
       DivSongTimestamps& ts=e->curSubSong->ts;
 
       String timeFormatted=ts.totalTime.toString(-1,TA_TIME_FORMAT_AUTO);
-      ImGui::Text("song duration: %s (%d ticks; %d rows)",timeFormatted.c_str(),ts.totalTicks,ts.totalRows);
+      ImGui::Text("song duration: %s (%" PRIu64 " ticks; %d rows)",timeFormatted.c_str(),ts.totalTicks,ts.totalRows);
       if (ts.isLoopDefined) {
         ImGui::Text("loop region is defined");
       } else {
diff --git a/src/main.cpp b/src/main.cpp
index 28706699e..51bc477f5 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -539,8 +539,10 @@ TAParamResult pBenchmark(String val) {
     benchMode=1;
   } else if (val=="seek") {
     benchMode=2;
+  } else if (val=="walk") {
+    benchMode=3;
   } else {
-    logE("invalid value for benchmark! valid values are: render and seek.");
+    logE("invalid value for benchmark! valid values are: render, seek and walk.");
     return TA_PARAM_ERROR;
   }
   e.setAudio(DIV_AUDIO_DUMMY);
@@ -653,7 +655,7 @@ void initParams() {
   params.push_back(TAParam("S","safemode",false,pSafeMode,"","enable safe mode (software rendering and no audio)"));
   params.push_back(TAParam("A","safeaudio",false,pSafeModeAudio,"","enable safe mode (with audio"));
 
-  params.push_back(TAParam("B","benchmark",true,pBenchmark,"render|seek","run performance test"));
+  params.push_back(TAParam("B","benchmark",true,pBenchmark,"render|seek|walk","run performance test"));
 
   params.push_back(TAParam("V","version",false,pVersion,"","view information about Furnace."));
   params.push_back(TAParam("W","warranty",false,pWarranty,"","view warranty disclaimer."));
@@ -1031,7 +1033,9 @@ int main(int argc, char** argv) {
 
   if (benchMode) {
     logI("starting benchmark!");
-    if (benchMode==2) {
+    if (benchMode==3) {
+      e.benchmarkWalk();
+    } else if (benchMode==2) {
       e.benchmarkSeek();
     } else {
       e.benchmarkPlayback();