diff --git a/src/asynStreamGeneratorDriver.cpp b/src/asynStreamGeneratorDriver.cpp
index f76055e..5ba860b 100644
--- a/src/asynStreamGeneratorDriver.cpp
+++ b/src/asynStreamGeneratorDriver.cpp
@@ -477,10 +477,13 @@ void asynStreamGeneratorDriver::processEvents() {
     // uint32. It does support int64 though.. so we start with that
     epicsInt32 *counts = new epicsInt32[this->num_channels];
 
+    const uint64_t minRateSamplePeriod = 100'000'000ll;
+    const size_t rateAverageWindow = 20;
     size_t countDiffsPtr = 0;
     epicsInt32 *rates = new epicsInt32[this->num_channels];
     epicsInt32 *countDiff = new epicsInt32[this->num_channels];
-    epicsInt32 *countDiffs = new epicsInt32[this->num_channels * 10];
+    epicsInt32 *countDiffs = new epicsInt32[this->num_channels * rateAverageWindow];
+    uint64_t *timeSpans = new uint64_t[this->num_channels];
     epicsTimeStamp lastRateUpdate = epicsTime::getCurrent();
 
     asynStatus status = asynSuccess;
@@ -613,23 +616,30 @@ void asynStreamGeneratorDriver::processEvents() {
         // Careful changing any of these magic numbers until I clean this up
         // as you might end up calculating the wrong rate
         epicsTimeStamp currentTime = epicsTime::getCurrent();
-        if (epicsTimeDiffInNS(&currentTime, &lastRateUpdate) > 100'000'000ll) {
+        if (epicsTimeDiffInNS(&currentTime, &lastRateUpdate) > minRateSamplePeriod) {
+            timeSpans[countDiffsPtr] = epicsTimeDiffInNS(&currentTime, &lastRateUpdate);
+
+	    uint64_t totalTime = 0;
+	    for (size_t i = 0; i <= rateAverageWindow; ++i) {
+		totalTime += timeSpans[i];
+	    }
+
             lastRateUpdate = currentTime;
 
             for (size_t i = 0; i <= this->num_channels; ++i) {
-                countDiffs[i * 10 + countDiffsPtr] = countDiff[i];
+                countDiffs[i * rateAverageWindow + countDiffsPtr] = countDiff[i];
 
                 uint64_t cnt = 0;
-                for (size_t j = 0; j <= 10; ++j) {
-                    cnt += countDiffs[i * 10 + j];
+                for (size_t j = 0; j <= rateAverageWindow; ++j) {
+                    cnt += countDiffs[i * rateAverageWindow + j];
                 }
                 rates[i] =
-                    cnt; // would / 10 to average than * 10 as want per second
+                    cnt / (totalTime * 1e-9);
 
                 countDiff[i] = 0;
             }
 
-            countDiffsPtr = (countDiffsPtr + 1) % 10;
+            countDiffsPtr = (countDiffsPtr + 1) % rateAverageWindow;
 
             if (countDiffsPtr % 5 == 0) {
                 lock();