diff --git a/tlsfuzzer/analysis.py b/tlsfuzzer/analysis.py
index 6c8c91e7..94e98b48 100644
--- a/tlsfuzzer/analysis.py
+++ b/tlsfuzzer/analysis.py
@@ -698,7 +698,8 @@ def _bootstrap_differences(self, pair, reps=5000):
         _diffs = data.iloc[:, pair.index2] -\
             data.iloc[:, pair.index1]
 
-        job_size = os.cpu_count() * 10
+        job_count = os.cpu_count() * 4
+        job_size = max(reps // job_count, 1)
 
         keys = ("mean", "median", "trim_mean_05", "trim_mean_25", "trimean")
 
@@ -708,7 +709,7 @@ def _bootstrap_differences(self, pair, reps=5000):
                 as pool:
             cent_tend = pool.imap_unordered(
                 self._cent_tend_of_random_sample,
-                chain(repeat(job_size, reps//job_size), [reps % job_size]))
+                chain(repeat(job_size, reps // job_size), [reps % job_size]))
 
             for values in cent_tend:
                 # handle reps % job_size == 0