diff --git a/extern/vgsound_emu-modified/vgsound_emu/src/es550x/es5506.cpp b/extern/vgsound_emu-modified/vgsound_emu/src/es550x/es5506.cpp
index 4860c0bde..548202a29 100644
--- a/extern/vgsound_emu-modified/vgsound_emu/src/es550x/es5506.cpp
+++ b/extern/vgsound_emu-modified/vgsound_emu/src/es550x/es5506.cpp
@@ -99,7 +99,7 @@ void es5506_core::voice_t::tick(u8 voice)
 
 	if (m_alu.busy())
 	{
-                fetch(0);
+          if ((m_alu.m_last_accum&(~m_alu.m_fraction))!=(m_alu.m_accum&(~m_alu.m_fraction))) fetch(0);
          	m_filter.tick(m_alu.interpolation());
 		// Send to output
 		m_output[0] = m_mute ? 0 : volume_calc(m_lvol, (short)m_filter.o4_1());
diff --git a/extern/vgsound_emu-modified/vgsound_emu/src/es550x/es550x.hpp b/extern/vgsound_emu-modified/vgsound_emu/src/es550x/es550x.hpp
index 0a9780fcf..2137cb246 100644
--- a/extern/vgsound_emu-modified/vgsound_emu/src/es550x/es550x.hpp
+++ b/extern/vgsound_emu-modified/vgsound_emu/src/es550x/es550x.hpp
@@ -169,6 +169,7 @@ class es550x_shared_core : public vgsound_emu_core
 							, m_start(0)
 							, m_end(0)
 							, m_accum(0)
+              , m_last_accum(0)
               , m_sample{0,0}
 						{
 						}
@@ -268,7 +269,7 @@ class es550x_shared_core : public vgsound_emu_core
 
 						inline s32 sample(u8 slot) { return m_sample[slot & 1]; }
 
-					private:
+					public:
 						class es550x_alu_cr_t : public vgsound_emu_core
 						{
 							public:
@@ -370,6 +371,7 @@ class es550x_shared_core : public vgsound_emu_core
 						// 20 integer, 9 fraction for ES5504/ES5505
 						// 21 integer, 11 fraction for ES5506
 						u32 m_accum = 0;
+            u32 m_last_accum = 0;
 						// Samples
 						s32 m_sample[2];
 				};
diff --git a/extern/vgsound_emu-modified/vgsound_emu/src/es550x/es550x_alu.cpp b/extern/vgsound_emu-modified/vgsound_emu/src/es550x/es550x_alu.cpp
index b0621ef77..f5849d0dd 100644
--- a/extern/vgsound_emu-modified/vgsound_emu/src/es550x/es550x_alu.cpp
+++ b/extern/vgsound_emu-modified/vgsound_emu/src/es550x/es550x_alu.cpp
@@ -16,6 +16,7 @@ void es550x_shared_core::es550x_voice_t::es550x_alu_t::reset()
 	m_start		= 0;
 	m_end		= 0;
 	m_accum		= 0;
+  m_last_accum=0;
 	m_sample[0] = m_sample[1] = 0;
 }
 
@@ -23,6 +24,7 @@ bool es550x_shared_core::es550x_voice_t::es550x_alu_t::busy() { return !(m_cr.m_
 
 bool es550x_shared_core::es550x_voice_t::es550x_alu_t::tick()
 {
+  m_last_accum = m_accum;
 	if (m_cr.dir())
 	{
 		m_accum -= m_fc;
diff --git a/src/engine/platform/es5506.cpp b/src/engine/platform/es5506.cpp
index cf9be44e7..556c54926 100644
--- a/src/engine/platform/es5506.cpp
+++ b/src/engine/platform/es5506.cpp
@@ -1153,14 +1153,15 @@ void DivPlatformES5506::notifyInsDeletion(void* ins) {
 void DivPlatformES5506::setFlags(const DivConfig& flags) {
   chipClock=16000000;
   CHECK_CUSTOM_CLOCK;
-  rate=chipClock/512; // 2 E clock tick (16 CLKIN tick) per voice / 4
-  for (int i=0; i<32; i++) {
-    oscBuf[i]->rate=rate;
-  }
 
   initChanMax=MAX(4,flags.getInt("channels",0x1f)&0x1f);
   chanMax=initChanMax;
   pageWriteMask(0x00,0x60,0x0b,chanMax);
+
+  rate=chipClock/(16*(initChanMax+1)); // 2 E clock tick (16 CLKIN tick) per voice / 4
+  for (int i=0; i<32; i++) {
+    oscBuf[i]->rate=rate;
+  }
 }
 
 void DivPlatformES5506::poke(unsigned int addr, unsigned short val) {
diff --git a/src/engine/platform/sound/c64_fp/siddefs-fp.h b/src/engine/platform/sound/c64_fp/siddefs-fp.h
index 439008621..3719925fc 100644
--- a/src/engine/platform/sound/c64_fp/siddefs-fp.h
+++ b/src/engine/platform/sound/c64_fp/siddefs-fp.h
@@ -21,10 +21,14 @@
 #define SIDDEFS_FP_H
 
 // Compilation configuration.
-#define RESID_BRANCH_HINTS 0
+#define RESID_BRANCH_HINTS 1
 
 // Compiler specifics.
+#if defined(__GNUC__) && (__GNUC__ >= 4)
+#define HAVE_BUILTIN_EXPECT 1
+#else
 #define HAVE_BUILTIN_EXPECT 0
+#endif
 
 #ifndef M_PI
 #  define M_PI    3.14159265358979323846