diff --git a/AMDRyzenCPUPowerManagement/AMDRyzenCPUPowerManagement.cpp b/AMDRyzenCPUPowerManagement/AMDRyzenCPUPowerManagement.cpp
index 7f9b67e..310434f 100644
--- a/AMDRyzenCPUPowerManagement/AMDRyzenCPUPowerManagement.cpp
+++ b/AMDRyzenCPUPowerManagement/AMDRyzenCPUPowerManagement.cpp
@@ -39,20 +39,20 @@ bool AMDRyzenCPUPowerManagement::init(OSDictionary *dictionary){
     IOLog("AMDCPUSupport v%s, init\n", xStringify(MODULE_VERSION));
     
     IOLog("AMDCPUSupport::enter dlinking..\n");
-    
+
     pmRyzen_symtable_ready = 0;
-    
+
 retry:
     find_mach_header_addr(getKernelVersion() >= KernelVersion::BigSur);
     pmRyzen_symtable._wrmsr_carefully = lookup_symbol("_wrmsr_carefully");
-    
+
     if(!pmRyzen_symtable._wrmsr_carefully){
         kextloadAlerts++;
         IOSleep(2);
         goto retry;
     }
-    
-    
+
+
     pmRyzen_symtable._KUNCUserNotificationDisplayAlert = lookup_symbol("_KUNCUserNotificationDisplayAlert");
     pmRyzen_symtable._cpu_to_processor = lookup_symbol("_cpu_to_processor");
     pmRyzen_symtable._tscFreq = lookup_symbol("_tscFreq");
@@ -145,7 +145,7 @@ void AMDRyzenCPUPowerManagement::startWorkLoop() {
 
                 //Read PStateDef generated by EFI.
                 if(pmRyzen_cpu_is_master(cpu_num))
-                    provider->dumpPstate();
+                    provider->dumpPstate(nullptr);
 
 
                 if(!pmRyzen_cpu_primary_in_core(cpu_num)) return;
@@ -320,11 +320,11 @@ bool AMDRyzenCPUPowerManagement::start(IOService *provider){
         IOLog("AMDCPUSupport::start no PCI support found, failing...\n");
         return false;
     }
-    
+
 //    while (!pmRyzen_symtable_ready) {
 //        IOSleep(200);
 //    }
-    
+
     void *safe_wrmsr = pmRyzen_symtable._wrmsr_carefully;
     if(!safe_wrmsr){
         IOLog("AMDCPUSupport::start WARN: Can't find _wrmsr_carefully, proceeding with unsafe wrmsr\n");
@@ -390,12 +390,17 @@ IOReturn AMDRyzenCPUPowerManagement::setPowerState(unsigned long powerStateOrdin
     if (0 == powerStateOrdinal) {
         // Going to sleep
         IOLog("AMDCPUSupport::setPowerState preparing for sleep\n");
-        wentToSleep = true;
+        sleepState.sleep = true;
+        sleepState.cpb = getCPBState();
+        //dumpPstate(sleepState.pstate);
+        
         stopWorkLoop();
-    } else if (1 == powerStateOrdinal && wentToSleep) {
+    } else if (1 == powerStateOrdinal && sleepState.sleep) {
         // Waking up
         IOLog("AMDCPUSupport::setPowerState preparing for wakeup\n");
-        wentToSleep = false;
+        sleepState.sleep = false;
+        setCPBState(sleepState.cpb);
+        //writePstate(sleepState.pstate);
         startWorkLoop();
     }
 
@@ -510,18 +515,20 @@ void AMDRyzenCPUPowerManagement::calculateEffectiveFrequency(uint8_t physical){
     //If an overflow of either the MPERF or APERF register occurs between read of last MPERF and
     //read of last APERF, the effective frequency calculated in is invalid.
     if(APERF <= lastAPERF || MPERF <= lastMPERF) {
-//        IOLog("AMDCPUSupport::calculateEffectiveFrequency: frequency is invalid!!!");
+        IOLog("AMDCPUSupport::calculateEffectiveFrequency: frequency is invalid for %u", physical);
+        lastAPERF_PerCore[physical] = APERF;
+        lastMPERF_PerCore[physical] = MPERF;
         return;
     }
     
     float freqP0 = PStateDefClock_perCore[0];
     
     uint64_t deltaAPERF = APERF - lastAPERF;
-    float effFreq = ((float)deltaAPERF / (float)(MPERF - lastMPERF)) * freqP0;
-    
-    effFreq_perCore[physical] = effFreq;
-    
-
+    uint64_t deltaMPERF = MPERF - lastMPERF;
+    if (deltaMPERF != 0) {
+        float effFreq = ((float)deltaAPERF / (float)(deltaMPERF)) * freqP0;
+        effFreq_perCore[physical] = effFreq;
+    }
 }
 
 void AMDRyzenCPUPowerManagement::updateInstructionDelta(uint8_t cpu_num){
@@ -633,9 +640,8 @@ void AMDRyzenCPUPowerManagement::updatePackageEnergy(){
     pwrLastTSC = rdtsc64();
 }
 
-void AMDRyzenCPUPowerManagement::dumpPstate(){
+void AMDRyzenCPUPowerManagement::dumpPstate(uint64_t buf[8]){
     
-    uint8_t len = 0;
     for (uint32_t i = 0; i < kMSR_PSTATE_LEN; i++) {
         uint64_t msr_value_buf = 0;
         bool err = !read_msr(kMSR_PSTATE_0 + i, &msr_value_buf);
@@ -654,17 +660,12 @@ void AMDRyzenCPUPowerManagement::dumpPstate(){
         PStateDef_perCore[i] = msr_value_buf;
         PStateDefClock_perCore[i] = clock;
         
-        if(msr_value_buf & ((uint64_t)1 << 63)) len++;
-        //        IOLog("a: %llu", msr_value_buf);
-    }
-    
-    PStateEnabledLen = max(PStateEnabledLen, len);
+        if(buf != nullptr) buf[i] = msr_value_buf;
+    };
 }
 
 void AMDRyzenCPUPowerManagement::writePstate(const uint64_t *buf){
     
-    PStateEnabledLen = 0;
-    
     //A bit hacky but at least works for now.
     void* args[] = {this, (void*)buf};
     
@@ -687,7 +688,7 @@ void AMDRyzenCPUPowerManagement::writePstate(const uint64_t *buf){
     
         
         if(!pmRyzen_cpu_is_master(cpu_number())) return;
-        provider->dumpPstate();
+        provider->dumpPstate(nullptr);
         
     }, nullptr, args);
         
@@ -725,7 +726,7 @@ EXPORT extern "C" kern_return_t amdryzencpupm_kern_start(kmod_info_t *, void *)
     // This works better and increases boot speed in some cases.
     PE_parse_boot_argn("liludelay", &ADDPR(debugPrintDelay), sizeof(ADDPR(debugPrintDelay)));
     ADDPR(debugEnabled) = checkKernelArgument("-amdpdbg");
-    
+
 //    IOLog("AMDCPUSupport::enter dlinking..\n");
 //
 //    pmRyzen_symtable_ready = 0;
@@ -741,7 +742,7 @@ EXPORT extern "C" kern_return_t amdryzencpupm_kern_start(kmod_info_t *, void *)
 //    pmRyzen_symtable._i386_cpu_IPI = lookup_symbol("_i386_cpu_IPI");
 //    pmRyzen_symtable_ready = 1;
 //    IOLog("AMDCPUSupport::enter link finished.\n");
-    
+
     return KERN_SUCCESS;
 }
 
diff --git a/AMDRyzenCPUPowerManagement/AMDRyzenCPUPowerManagement.hpp b/AMDRyzenCPUPowerManagement/AMDRyzenCPUPowerManagement.hpp
index 109319f..29d7ad9 100644
--- a/AMDRyzenCPUPowerManagement/AMDRyzenCPUPowerManagement.hpp
+++ b/AMDRyzenCPUPowerManagement/AMDRyzenCPUPowerManagement.hpp
@@ -78,6 +78,12 @@ typedef struct tctl_offset {
     int offset;
 } TempOffset;
 
+typedef struct sleep_state {
+    bool sleep;
+    bool cpb;
+    uint64_t pstate[8];
+} SleepState;
+
 
 static IOPMPowerState powerStates[kNrOfPowerStates] = {
    {1, kIOPMPowerOff, kIOPMPowerOff, kIOPMPowerOff, 0, 0, 0, 0, 0, 0, 0, 0},
@@ -159,7 +165,7 @@ class AMDRyzenCPUPowerManagement : public IOService {
     
     void registerRequest();
     
-    void dumpPstate();
+    void dumpPstate(uint64_t buf[8]);
     void writePstate(const uint64_t *buf);
     
     bool initSuperIO(uint16_t* chipIntel);
@@ -209,7 +215,6 @@ class AMDRyzenCPUPowerManagement : public IOService {
     uint8_t PStateCur_perCore[CPUInfo::MaxCpus];
     uint8_t PStateCtl = 0;
     uint64_t PStateDef_perCore[8];
-    uint8_t PStateEnabledLen = 0;
     float PStateDefClock_perCore[8];
     bool cpbSupported;
     
@@ -260,7 +265,8 @@ class AMDRyzenCPUPowerManagement : public IOService {
     KernelPatcher *liluKernelPatcher;
     
     bool getPCIService();
-    bool wentToSleep;
+    
+    SleepState sleepState;
     
     void startWorkLoop();
     void stopWorkLoop();