diff --git a/main/global_state.h b/main/global_state.h
index 0c3f28c..fcda4e3 100644
--- a/main/global_state.h
+++ b/main/global_state.h
@@ -14,7 +14,7 @@
 #define STRATUM_USER CONFIG_STRATUM_USER
 #define FALLBACK_STRATUM_USER CONFIG_FALLBACK_STRATUM_USER
 
-#define HISTORY_LENGTH 512
+#define HISTORY_LENGTH 100
 #define DIFF_STRING_SIZE 10
 
 typedef enum
@@ -41,9 +41,11 @@ typedef struct
 
 typedef struct
 {
+    double duration_start;
     int historical_hashrate_rolling_index;
-    uint64_t historical_hashrate_time_stamps[HISTORY_LENGTH];
+    double historical_hashrate_time_stamps[HISTORY_LENGTH];
     double historical_hashrate[HISTORY_LENGTH];
+    int historical_hashrate_init;
     double current_hashrate;
     double current_hashrate_10m;
     double current_hashrate_1h;
diff --git a/main/system.c b/main/system.c
index b1974d2..bb700d2 100644
--- a/main/system.c
+++ b/main/system.c
@@ -60,7 +60,9 @@ static void _init_system(GlobalState * GLOBAL_STATE)
 {
     SystemModule * module = &GLOBAL_STATE->SYSTEM_MODULE;
 
+    module->duration_start = 0;
     module->historical_hashrate_rolling_index = 0;
+    module->historical_hashrate_init = 0;
     memset(module->historical_hashrate, 0, sizeof(module->historical_hashrate));
     memset(module->historical_hashrate_time_stamps, 0, sizeof(module->historical_hashrate_time_stamps));
     module->current_hashrate = 0;
@@ -572,7 +574,9 @@ void SYSTEM_notify_rejected_share(GlobalState * GLOBAL_STATE)
 
 void SYSTEM_notify_mining_started(GlobalState * GLOBAL_STATE)
 {
+    SystemModule * module = &GLOBAL_STATE->SYSTEM_MODULE;
 
+    module->duration_start = esp_timer_get_time();
 }
 
 void SYSTEM_notify_new_ntime(GlobalState * GLOBAL_STATE, uint32_t ntime)
@@ -599,55 +603,37 @@ void SYSTEM_notify_found_nonce(GlobalState * GLOBAL_STATE)
 {
     SystemModule * module = &GLOBAL_STATE->SYSTEM_MODULE;
 
+    // Calculate the time difference in seconds with sub-second precision
     // hashrate = (nonce_difficulty * 2^32) / time_to_find
 
-    // let's calculate the 10min average hashrate
-    uint64_t time_period = 600 * 1e6;
-    uint64_t current_time = esp_timer_get_time();
-
-    int index = module->historical_hashrate_rolling_index;
+    module->historical_hashrate[module->historical_hashrate_rolling_index] = GLOBAL_STATE->initial_ASIC_difficulty;
+    module->historical_hashrate_time_stamps[module->historical_hashrate_rolling_index] = esp_timer_get_time();
 
-    module->historical_hashrate[index] = BM1366_INITIAL_DIFFICULTY;
-    module->historical_hashrate_time_stamps[index] = current_time;
+    module->historical_hashrate_rolling_index = (module->historical_hashrate_rolling_index + 1) % HISTORY_LENGTH;
 
+    // ESP_LOGI(TAG, "nonce_diff %.1f, ttf %.1f, res %.1f", nonce_diff, duration,
+    // historical_hashrate[historical_hashrate_rolling_index]);
 
+    if (module->historical_hashrate_init < HISTORY_LENGTH) {
+        module->historical_hashrate_init++;
+    } else {
+        module->duration_start =
+            module->historical_hashrate_time_stamps[(module->historical_hashrate_rolling_index + 1) % HISTORY_LENGTH];
+    }
     double sum = 0;
-    uint64_t oldest_time = 0;
-    int valid_shares = 0;
-    for (int i = 0; i < HISTORY_LENGTH; i++) {
-        // sum backwards
-        // avoid modulo of a negative number
-        int rindex = (index - i + HISTORY_LENGTH) % HISTORY_LENGTH;
-
-    uint64_t timestamp = module->historical_hashrate_time_stamps[rindex];
-
-    // zero timestamps indicate that the "slot" is not used
-        if (timestamp == 0) {
-            break;
-        }
-
-        // out of scope? break
-        if (current_time - timestamp > time_period) {
-            break;
-        }
-
-        sum += module->historical_hashrate[rindex];
-        oldest_time = timestamp;
-        valid_shares++;
+    for (int i = 0; i < module->historical_hashrate_init; i++) {
+        sum += module->historical_hashrate[i];
     }
 
-    // increment rolling index
-    // can't be done before summation
-    index = (index + 1) % HISTORY_LENGTH;
-    module->historical_hashrate_rolling_index = index;
+    double duration = (double) (esp_timer_get_time() - module->duration_start) / 1000000;
 
-    double rolling_rate = (sum * 4.294967296e9) / (double) (time_period / 1e6);
-    double rolling_rate_gh = rolling_rate / 1.0e9;
-
-    ESP_LOGI(TAG, "hashrate: %.3fGH%s shares: %d (historical buffer spans %ds)", rolling_rate_gh,
-             (current_time - oldest_time >= time_period) ? "" : "*", valid_shares, (int) ((current_time - oldest_time) / 1e6));
-
-    module->current_hashrate = rolling_rate_gh;
+    double rolling_rate = (sum * 4294967296) / (duration * 1000000000);
+    if (module->historical_hashrate_init < HISTORY_LENGTH) {
+        module->current_hashrate = rolling_rate;
+    } else {
+        // More smoothing
+        module->current_hashrate = ((module->current_hashrate * 9) + rolling_rate) / 10;
+    }
 
     _update_hashrate(GLOBAL_STATE);