diff --git a/selfdrive/test/process_replay/README.md b/selfdrive/test/process_replay/README.md
index e760e4e135..9fa4ca644a 100644
--- a/selfdrive/test/process_replay/README.md
+++ b/selfdrive/test/process_replay/README.md
@@ -5,6 +5,7 @@ Process replay is a regression test designed to identify any changes in the outp
 If the test fails, make sure that you didn't unintentionally change anything. If there are intentional changes, the reference logs will be updated.
 
 Use `test_processes.py` to run the test locally.
+Use `FILEREADER_CACHE='1' test_processes.py` to cache log files. 
 
 Currently the following processes are tested:
 
diff --git a/selfdrive/test/process_replay/test_processes.py b/selfdrive/test/process_replay/test_processes.py
index afab6cc765..694317d52f 100755
--- a/selfdrive/test/process_replay/test_processes.py
+++ b/selfdrive/test/process_replay/test_processes.py
@@ -131,12 +131,13 @@ def format_diff(results, ref_commit):
 
 
 if __name__ == "__main__":
-  parser = argparse.ArgumentParser(description="Regression test to identify changes in a process's output")
+  all_cars = {car for car, _ in segments}
+  all_procs = {cfg.proc_name for cfg in CONFIGS}
 
-  # whitelist has precedence over blacklist in case both are defined
-  parser.add_argument("--whitelist-procs", type=str, nargs="*", default=[],
+  parser = argparse.ArgumentParser(description="Regression test to identify changes in a process's output")
+  parser.add_argument("--whitelist-procs", type=str, nargs="*", default=all_procs,
                       help="Whitelist given processes from the test (e.g. controlsd)")
-  parser.add_argument("--whitelist-cars", type=str, nargs="*", default=[],
+  parser.add_argument("--whitelist-cars", type=str, nargs="*", default=all_cars,
                       help="Whitelist given cars from the test (e.g. HONDA)")
   parser.add_argument("--blacklist-procs", type=str, nargs="*", default=[],
                       help="Blacklist given processes from the test (e.g. controlsd)")
@@ -153,6 +154,10 @@ if __name__ == "__main__":
   parser.add_argument("-j", "--jobs", type=int, default=1)
   args = parser.parse_args()
 
+  tested_procs = set(args.whitelist_procs) - set(args.blacklist_procs)
+  tested_cars = set(args.whitelist_cars) - set(args.blacklist_cars)
+  tested_cars = {c.upper() for c in tested_cars}
+
   full_test = all(len(x) == 0 for x in (args.whitelist_procs, args.whitelist_cars, args.blacklist_procs, args.blacklist_cars, args.ignore_fields, args.ignore_msgs))
   upload = args.update_refs or args.upload_only
   os.makedirs(os.path.dirname(FAKEDATA), exist_ok=True)
@@ -180,20 +185,19 @@ if __name__ == "__main__":
 
   with concurrent.futures.ProcessPoolExecutor(max_workers=args.jobs) as pool:
     if not args.upload_only:
-      lreaders: Any = {}
-      p1 = pool.map(get_logreader, [seg for car, seg in segments])
-      for (segment, lr) in tqdm(p1, desc="Getting Logs", total=len(segments)):
+      download_segments = [seg for car, seg in segments if car in tested_cars]
+      lreaders: Dict[str, LogReader] = {}
+      p1 = pool.map(get_logreader, download_segments)
+      for segment, lr in tqdm(p1, desc="Getting Logs", total=len(download_segments)):
         lreaders[segment] = lr
 
     pool_args: Any = []
     for car_brand, segment in segments:
-      if (len(args.whitelist_cars) and car_brand.upper() not in args.whitelist_cars) or \
-         (not len(args.whitelist_cars) and car_brand.upper() in args.blacklist_cars):
+      if car_brand not in tested_cars:
         continue
 
       for cfg in CONFIGS:
-        if (len(args.whitelist_procs) and cfg.proc_name not in args.whitelist_procs) or \
-           (not len(args.whitelist_procs) and cfg.proc_name in args.blacklist_procs):
+        if cfg.proc_name not in tested_procs:
           continue
 
         cur_log_fn = os.path.join(FAKEDATA, f"{segment}_{cfg.proc_name}_{cur_commit}.bz2")