diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 3b1d9d6c5..05392127f 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -950,12 +950,13 @@ bool DivEngine::addSystem(DivSystem which) {
       unsigned int outs=disCont[i].dispatch->getOutputCount();
       if (outs>16) outs=16;
       if (outs<2) {
+        song.patchbay.reserve(DIV_MAX_OUTPUTS);
         for (unsigned int j=0; j<DIV_MAX_OUTPUTS; j++) {
           song.patchbay.push_back((i<<20)|j);
         }
       } else {
+        song.patchbay.reserve(outs);
         for (unsigned int j=0; j<outs; j++) {
-
           song.patchbay.push_back((i<<20)|(j<<16)|j);
         }
       }
@@ -1062,9 +1063,12 @@ bool DivEngine::swapSystem(int src, int dest, bool preserveOrder) {
 
     // prepare swap list
     int index=0;
+    swapList.reserve(song.systemLen);
     for (int i=0; i<song.systemLen; i++) {
       chanList.clear();
-      for (int j=0; j<getChannelCount(song.system[i]); j++) {
+      const int channelCount = getChannelCount(song.system[i]);
+      chanList.reserve(channelCount);
+      for (int j=0; j<channelCount; j++) {
         chanList.push_back(index);
         index++;
       }
@@ -1319,6 +1323,7 @@ void DivEngine::enableCommandStream(bool enable) {
 void DivEngine::getCommandStream(std::vector<DivCommand>& where) {
   BUSY_BEGIN;
   where.clear();
+  where.reserve(cmdStream.size());
   for (DivCommand& i: cmdStream) {
     where.push_back(i);
   }
@@ -2822,23 +2827,26 @@ void DivEngine::autoPatchbay() {
     unsigned int outs=disCont[i].dispatch->getOutputCount();
     if (outs>16) outs=16;
     if (outs<2) {
+      song.patchbay.reserve(DIV_MAX_OUTPUTS);
       for (unsigned int j=0; j<DIV_MAX_OUTPUTS; j++) {
         song.patchbay.push_back((i<<20)|j);
       }
     } else {
+      song.patchbay.reserve(outs);
       for (unsigned int j=0; j<outs; j++) {
-
         song.patchbay.push_back((i<<20)|(j<<16)|j);
       }
     }
   }
 
   // wave/sample preview
+  song.patchbay.reserve(DIV_MAX_OUTPUTS);
   for (unsigned int j=0; j<DIV_MAX_OUTPUTS; j++) {
     song.patchbay.push_back(0xffd00000|j);
   }
 
   // metronome
+  song.patchbay.reserve(DIV_MAX_OUTPUTS);
   for (unsigned int j=0; j<DIV_MAX_OUTPUTS; j++) {
     song.patchbay.push_back(0xffe00000|j);
   }
diff --git a/src/engine/export/amigaValidation.cpp b/src/engine/export/amigaValidation.cpp
index dc836f33e..56d3814a7 100644
--- a/src/engine/export/amigaValidation.cpp
+++ b/src/engine/export/amigaValidation.cpp
@@ -266,6 +266,7 @@ std::vector<DivROMExportOutput> DivExportAmigaValidation::go(DivEngine* e) {
   }
 
   // finish
+  ret.reserve(5);
   ret.push_back(DivROMExportOutput("sbook.bin",sbook));
   ret.push_back(DivROMExportOutput("wbook.bin",wbook));
   ret.push_back(DivROMExportOutput("sample.bin",sample));
diff --git a/src/engine/fileOps.cpp b/src/engine/fileOps.cpp
index 1465c816e..746f59046 100644
--- a/src/engine/fileOps.cpp
+++ b/src/engine/fileOps.cpp
@@ -342,6 +342,7 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
       ds.insLen=16;
     }
     logI("reading instruments (%d)...",ds.insLen);
+    ds.ins.reserve(ds.insLen);
     for (int i=0; i<ds.insLen; i++) {
       DivInstrument* ins=new DivInstrument;
       unsigned char mode=0;
@@ -669,6 +670,7 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
     if (ds.version>0x0b) {
       ds.waveLen=(unsigned char)reader.readC();
       logI("reading wavetables (%d)...",ds.waveLen);
+      ds.wave.reserve(ds.waveLen);
       for (int i=0; i<ds.waveLen; i++) {
         DivWavetable* wave=new DivWavetable;
         wave->len=(unsigned char)reader.readI();
@@ -838,6 +840,7 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
       // it appears this byte stored the YMU759 sample rate
       ymuSampleRate=reader.readC();
     }
+    ds.sample.reserve(ds.sampleLen);
     for (int i=0; i<ds.sampleLen; i++) {
       DivSample* sample=new DivSample;
       int length=reader.readI();
@@ -2127,6 +2130,7 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
     for (int i=0; i<ds.sampleLen; i++) {
       samplePtr[i]=reader.readI();
     }
+    patPtr.reserve(numberOfPats);
     for (int i=0; i<numberOfPats; i++) patPtr.push_back(reader.readI());
 
     logD("reading orders (%d)...",subSong->ordersLen);
@@ -2345,6 +2349,7 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
 
       // patchbay
       unsigned int conns=reader.readI();
+      ds.patchbay.reserve(conns);
       for (unsigned int i=0; i<conns; i++) {
         ds.patchbay.push_back((unsigned int)reader.readI());
       }
@@ -2377,6 +2382,7 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
 
       // grooves
       unsigned char grooveCount=reader.readC();
+      ds.grooves.reserve(grooveCount);
       for (int i=0; i<grooveCount; i++) {
         DivGroovePattern gp;
         gp.len=reader.readC();
@@ -2477,6 +2483,7 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
 
     // read subsongs
     if (ds.version>=95) {
+      ds.subsong.reserve(numberOfSubSongs);
       for (int i=0; i<numberOfSubSongs; i++) {
         ds.subsong.push_back(new DivSubSong);
         if (!reader.seek(subSongPtr[i],SEEK_SET)) {
@@ -2558,6 +2565,7 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
     }
 
     // read instruments
+    ds.ins.reserve(ds.insLen);
     for (int i=0; i<ds.insLen; i++) {
       DivInstrument* ins=new DivInstrument;
       logD("reading instrument %d at %x...",i,insPtr[i]);
@@ -2582,6 +2590,7 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
     }
 
     // read wavetables
+    ds.wave.reserve(ds.waveLen);
     for (int i=0; i<ds.waveLen; i++) {
       DivWavetable* wave=new DivWavetable;
       logD("reading wavetable %d at %x...",i,wavePtr[i]);
@@ -2606,6 +2615,7 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
     }
 
     // read samples
+    ds.sample.reserve(ds.sampleLen);
     for (int i=0; i<ds.sampleLen; i++) {
       DivSample* sample=new DivSample;
 
@@ -3069,6 +3079,7 @@ bool DivEngine::loadMod(unsigned char* file, size_t len) {
 
     // samples
     logD("reading samples... (%d)",insCount);
+    ds.sample.reserve(insCount);
     for (int i=0; i<insCount; i++) {
       DivSample* sample=new DivSample;
       sample->depth=DIV_SAMPLE_DEPTH_8BIT;
@@ -3373,6 +3384,7 @@ bool DivEngine::loadMod(unsigned char* file, size_t len) {
     }
     
     // instrument creation
+    ds.ins.reserve(insCount);
     for(int i=0; i<insCount; i++) {
       DivInstrument* ins=new DivInstrument;
       ins->type=DIV_INS_AMIGA;
@@ -3651,6 +3663,7 @@ bool DivEngine::loadS3M(unsigned char* file, size_t len) {
     }
 
     // load instruments/samples
+    ds.ins.reserve(ds.insLen);
     for (int i=0; i<ds.insLen; i++) {
       DivInstrument* ins=new DivInstrument;
       if (!reader.seek(0x4c+insPtr[i]*16,SEEK_SET)) {
@@ -3877,6 +3890,7 @@ bool DivEngine::loadFC(unsigned char* file, size_t len) {
     // sequences
     seqLen/=13;
     logD("reading sequences... (%d)",seqLen);
+    seq.reserve(seqLen);
     for (unsigned int i=0; i<seqLen; i++) {
       FCSequence s;
       for (int j=0; j<4; j++) {
@@ -3906,6 +3920,7 @@ bool DivEngine::loadFC(unsigned char* file, size_t len) {
     }
     patLen/=64;
     logD("reading patterns... (%d)",patLen);
+    pat.reserve(patLen);
     for (unsigned int i=0; i<patLen; i++) {
       FCPattern p;
       logV("- pattern %d",i);
@@ -3926,6 +3941,7 @@ bool DivEngine::loadFC(unsigned char* file, size_t len) {
     }
     freqMacroLen/=64;
     logD("reading freq sequences... (%d)",freqMacroLen);
+    freqMacros.reserve(freqMacroLen);
     for (unsigned int i=0; i<freqMacroLen; i++) {
       FCMacro m;
       reader.read(m.val,64);
@@ -3941,6 +3957,7 @@ bool DivEngine::loadFC(unsigned char* file, size_t len) {
     }
     volMacroLen/=64;
     logD("reading volume sequences... (%d)",volMacroLen);
+    volMacros.reserve(volMacroLen);
     for (unsigned int i=0; i<volMacroLen; i++) {
       FCMacro m;
       reader.read(m.val,64);
@@ -3955,6 +3972,7 @@ bool DivEngine::loadFC(unsigned char* file, size_t len) {
       return false;
     }
     logD("reading samples...");
+    ds.sample.reserve(10);
     for (int i=0; i<10; i++) {
       DivSample* s=new DivSample;
       s->depth=DIV_SAMPLE_DEPTH_8BIT;
@@ -3981,6 +3999,7 @@ bool DivEngine::loadFC(unsigned char* file, size_t len) {
         return false;
       }
       logD("reading wavetables...");
+      ds.wave.reserve(80);
       for (int i=0; i<80; i++) {
         DivWavetable* w=new DivWavetable;
         w->min=0;
@@ -4009,6 +4028,7 @@ bool DivEngine::loadFC(unsigned char* file, size_t len) {
       }
     } else {
       // generate preset waves
+      ds.wave.reserve(48);
       for (int i=0; i<48; i++) {
         DivWavetable* w=new DivWavetable;
         generateFCPresetWave(i,w);
@@ -4156,6 +4176,7 @@ bool DivEngine::loadFC(unsigned char* file, size_t len) {
 
       // volume sequence
       ins->std.volMacro.len=0;
+      ds.ins.reserve(64 - 5);
       for (int j=5; j<64; j++) {
         loopMap[j]=ins->std.volMacro.len;
         if (m.val[j]==0xe1) { // end
@@ -4553,6 +4574,7 @@ bool DivEngine::loadFTM(unsigned char* file, size_t len) {
         CHECK_BLOCK_VERSION(4);
         unsigned char totalSongs=reader.readC();
         logV("%d songs:",totalSongs+1);
+        ds.subsong.reserve(totalSongs);
         for (int i=0; i<=totalSongs; i++) {
           String subSongName=reader.readString();
           ds.subsong.push_back(new DivSubSong);
@@ -5087,12 +5109,14 @@ DivDataErrors DivEngine::readAssetDirData(SafeReader& reader, std::vector<DivAss
 
   unsigned int numDirs=reader.readI();
 
+  dir.reserve(numDirs);
   for (unsigned int i=0; i<numDirs; i++) {
     DivAssetDir d;
 
     d.name=reader.readString();
     unsigned short numEntries=reader.readS();
 
+    d.entries.reserve(numEntries);
     for (unsigned short j=0; j<numEntries; j++) {
       d.entries.push_back(((unsigned char)reader.readC()));
     }
@@ -5425,6 +5449,7 @@ SafeWriter* DivEngine::saveFur(bool notPrimary, bool newPatternFormat) {
   w->seek(0,SEEK_END);
 
   /// SUBSONGS
+  subSongPtr.reserve(song.subsong.size() - 1);
   for (subSongIndex=1; subSongIndex<song.subsong.size(); subSongIndex++) {
     subSong=song.subsong[subSongIndex];
     subSongPtr.push_back(w->tell());
@@ -5486,6 +5511,7 @@ SafeWriter* DivEngine::saveFur(bool notPrimary, bool newPatternFormat) {
   }
 
   /// CHIP FLAGS
+  sysFlagsPtr.reserve(song.systemLen);
   for (int i=0; i<song.systemLen; i++) {
     String data=song.systemFlags[i].toString();
     if (data.empty()) {
@@ -5515,6 +5541,7 @@ SafeWriter* DivEngine::saveFur(bool notPrimary, bool newPatternFormat) {
   putAssetDirData(w,song.sampleDir);
 
   /// INSTRUMENT
+  insPtr.reserve(song.insLen);
   for (int i=0; i<song.insLen; i++) {
     DivInstrument* ins=song.ins[i];
     insPtr.push_back(w->tell());
@@ -5522,6 +5549,7 @@ SafeWriter* DivEngine::saveFur(bool notPrimary, bool newPatternFormat) {
   }
 
   /// WAVETABLE
+  wavePtr.reserve(song.waveLen);
   for (int i=0; i<song.waveLen; i++) {
     DivWavetable* wave=song.wave[i];
     wavePtr.push_back(w->tell());
@@ -5529,6 +5557,7 @@ SafeWriter* DivEngine::saveFur(bool notPrimary, bool newPatternFormat) {
   }
 
   /// SAMPLE
+  samplePtr.reserve(song.sampleLen);
   for (int i=0; i<song.sampleLen; i++) {
     DivSample* sample=song.sample[i];
     samplePtr.push_back(w->tell());
@@ -5536,6 +5565,7 @@ SafeWriter* DivEngine::saveFur(bool notPrimary, bool newPatternFormat) {
   }
 
   /// PATTERN
+  patPtr.reserve(patsToWrite.size());
   for (PatToWrite& i: patsToWrite) {
     DivPattern* pat=song.subsong[i.subsong]->pat[i.chan].getPattern(i.pat,false);
     patPtr.push_back(w->tell());