diff --git a/src/cpucounters.cpp b/src/cpucounters.cpp
index 5368fe61..34e2a70d 100644
--- a/src/cpucounters.cpp
+++ b/src/cpucounters.cpp
@@ -359,7 +359,7 @@ bool PCM::isHWTMAL1Supported() const
 void PCM::readCPUMicrocodeLevel()
 {
     if (MSR.empty()) return;
-    const int ref_core = 0;
+    const int32 ref_core = socketRefCore[0];
     TemporalThreadAffinity affinity(ref_core);
     if (affinity.supported() && isCoreOnline(ref_core))
     {   // see "Update Signature and Verification" and "Determining the Signature"
@@ -1110,7 +1110,22 @@ bool PCM::discoverSystemTopology()
     };
     std::unordered_map<int, domain> topologyDomainMap;
     {
-        TemporalThreadAffinity aff0(0);
+        const int32 maxTopoDomainAff = 1<<16;
+        int32 topoDomainAff = -1;
+
+        for (int32 core = 0; core < maxTopoDomainAff; ++core)
+        {
+            try {
+                TemporalThreadAffinity _(core);
+                topoDomainAff = core;
+            }
+            catch (...)
+            {
+            }
+            if (topoDomainAff != -1) break;
+        }
+
+        TemporalThreadAffinity _(topoDomainAff);
 
         if (initCoreMasks(smtMaskWidth, coreMaskWidth, l2CacheMaskShift, l3CacheMaskShift) == false)
         {
@@ -4637,7 +4652,7 @@ uint64 RDTSC();
 
 void PCM::computeNominalFrequency()
 {
-    const int ref_core = 0;
+    const int32 ref_core = socketRefCore[0];
     const uint64 before = getInvariantTSC_Fast(ref_core);
     MySleepMs(100);
     const uint64 after = getInvariantTSC_Fast(ref_core);
@@ -4809,11 +4824,11 @@ void PCM::computeQPISpeedBeckton(int core_nr)
     MSR[core_nr]->read(R_MSR_PMON_CTR0, &startFlits);
 
     const uint64 timerGranularity = 1000000ULL; // mks
-    uint64 startTSC = getTickCount(timerGranularity, (uint32) core_nr);
+    uint64 startTSC = getTickCount(timerGranularity, core_nr);
     uint64 endTSC;
     do
     {
-        endTSC = getTickCount(timerGranularity, (uint32) core_nr);
+        endTSC = getTickCount(timerGranularity, core_nr);
     } while (endTSC - startTSC < 200000ULL); // spin for 200 ms
 
     uint64 endFlits = 0;
@@ -5401,8 +5416,9 @@ int convertUnknownToInt(size_t size, char* value)
 #endif
 
 
-uint64 PCM::getTickCount(uint64 multiplier, uint32 core)
+uint64 PCM::getTickCount(uint64 multiplier, int32 core)
 {
+    if (core == -1) core = socketRefCore[0];
     return (multiplier * getInvariantTSC_Fast(core)) / getNominalFrequency();
 }
 
diff --git a/src/cpucounters.h b/src/cpucounters.h
index b3e60ab5..90b5ecf9 100644
--- a/src/cpucounters.h
+++ b/src/cpucounters.h
@@ -2304,9 +2304,9 @@ class PCM_API PCM
     }
     //! \brief Return TSC timer value in time units
     //! \param multiplier use 1 for seconds, 1000 for ms, 1000000 for mks, etc (default is 1000: ms)
-    //! \param core core to read on-chip TSC value (default is 0)
+    //! \param core core to read on-chip TSC value (default is -1: socketRefCore[0])
     //! \return time counter value
-    uint64 getTickCount(uint64 multiplier = 1000 /* ms */, uint32 core = 0);
+    uint64 getTickCount(uint64 multiplier = 1000 /* ms */, int32 core = -1);
 
     uint64 getInvariantTSC_Fast(uint32 core = 0);