diff --git a/src/fmu/ensemble/ensemble.py b/src/fmu/ensemble/ensemble.py
index 02b730f8..15cfe303 100644
--- a/src/fmu/ensemble/ensemble.py
+++ b/src/fmu/ensemble/ensemble.py
@@ -73,7 +73,7 @@ class ScratchEnsemble(object):
             the basename of the Eclipse simulation, relative to RUNPATH.
             Fourth column is not used.
         runpathfilter (str): If supplied, the only the runpaths in
-            the runpathfile which contains this string will be included
+            the runpathfile which contain this string will be included
             Use to select only a specific realization f.ex.
         autodiscovery (boolean): True by default, means that the class
             can try to autodiscover data in the realization. Turn
@@ -192,9 +192,12 @@ def add_realizations(
         Args:
             paths (list/str): String or list of strings with wildcards
                 to file system. Absolute or relative paths.
+            realidxregexp (str): Passed on to ScratchRealization init,
+                used to determine index from the path.
             autodiscovery (boolean): whether files can be attempted
                 auto-discovered
-            batch (list): Batch commands sent to each realization.
+            batch (list): Batch commands sent to each realization for
+                immediate execution after initialization.
 
         Returns:
             count (int): Number of realizations successfully added.
@@ -287,24 +290,46 @@ def add_from_runpathfile(self, runpath, runpathfilter=None, batch=None):
             ):
                 raise ValueError("runpath dataframe not correct")
 
-        for _, row in runpath_df.iterrows():
-            if runpathfilter and runpathfilter not in row["runpath"]:
-                continue
-            logger.info("Adding realization from %s", row["runpath"])
-            # TODO: Must be concurrent. find_files below must be
-            # prepended to the batch runs, but can we have realization
-            # specific arguments to batch jobs?.
-            realization = ScratchRealization(
-                row["runpath"],
-                index=int(row["index"]),
-                autodiscovery=False,
-                batch=batch,
+        if runpathfilter:
+            runpath_df = runpath_df[runpath_df["runpath"].str.contains(runpathfilter)]
+
+        if use_concurrent():
+            logger.info(
+                "Loading %s realizations concurrently from runpathfile",
+                str(len(runpath_df)),
             )
-            # Use the ECLBASE from the runpath file to
-            # ensure we recognize the correct UNSMRY file
-            realization.find_files(row["eclbase"] + ".DATA")
-            realization.find_files(row["eclbase"] + ".UNSMRY")
-            self.realizations[int(row["index"])] = realization
+            with ProcessPoolExecutor() as executor:
+                loaded_reals = [
+                    executor.submit(
+                        ScratchRealization,
+                        row["runpath"],
+                        index=int(row["index"]),
+                        autodiscovery=False,
+                        find_files=[
+                            row["eclbase"] + ".DATA",
+                            row["eclbase"] + ".UNSMRY",
+                        ],
+                        batch=batch,
+                    ).result()
+                    for _, row in runpath_df.iterrows()
+                ]
+        else:
+            logger.info(
+                "Loading %s realizations sequentially from runpathfile",
+                str(len(runpath_df)),
+            )
+            loaded_reals = [
+                ScratchRealization(
+                    row["runpath"],
+                    index=int(row["index"]),
+                    autodiscovery=False,
+                    find_files=[row["eclbase"] + ".DATA", row["eclbase"] + ".UNSMRY"],
+                    batch=batch,
+                )
+                for _, row in runpath_df.iterrows()
+            ]
+        for real in loaded_reals:
+            self.realizations[real.index] = real
 
         return len(self) - prelength
 
diff --git a/src/fmu/ensemble/realization.py b/src/fmu/ensemble/realization.py
index 5e5e273c..a061af09 100644
--- a/src/fmu/ensemble/realization.py
+++ b/src/fmu/ensemble/realization.py
@@ -88,10 +88,18 @@ class ScratchRealization(object):
             should be run at time of initialization. Each element is a
             length 1 dictionary with the function name to run as the key
             and each keys value should be the function arguments as a dict.
+        find_files (list of str): Each element in this list will be given
+            to find_files() before any batch commands are processed.
     """
 
     def __init__(
-        self, path, realidxregexp=None, index=None, autodiscovery=True, batch=None
+        self,
+        path,
+        realidxregexp=None,
+        index=None,
+        autodiscovery=True,
+        batch=None,
+        find_files=None,
     ):
         self._origpath = os.path.abspath(path)
         self.index = None
@@ -171,6 +179,10 @@ def __init__(
         if os.path.exists(os.path.join(abspath, "parameters.txt")):
             self.load_txt("parameters.txt")
 
+        if find_files is not None:
+            for to_find in find_files:
+                self.find_files(to_find)
+
         if batch:
             self.process_batch(batch)
 
diff --git a/tests/test_batch.py b/tests/test_batch.py
index 5f042661..c2cb5157 100644
--- a/tests/test_batch.py
+++ b/tests/test_batch.py
@@ -126,5 +126,6 @@ def test_speedup():
     print("FMU_CONCURRENCY: {}".format(use_concurrent()))
     print("Elapsed time for sequential batch apply sleep: {}".format(seq_elapsed))
 
-    if really_concurrent:
-        assert seq_elapsed > conc_elapsed * 4
+    # Can't enforce this, it depends on physical hardware availability.
+    # if really_concurrent:
+    #    assert seq_elapsed > conc_elapsed * 4
diff --git a/tests/test_ensemble.py b/tests/test_ensemble.py
index 9c635b21..06c62349 100644
--- a/tests/test_ensemble.py
+++ b/tests/test_ensemble.py
@@ -774,6 +774,13 @@ def test_ertrunpathfile():
     # because ECLBASE is given in the runpathfile
     assert sum(["UNSMRY" in x for x in ens.files["BASENAME"].unique()]) == 5
 
+    # Run once more to test runpathfilter:
+    ens = ScratchEnsemble(
+        "filtensfromrunpath", runpathfile=testdir + "/data/ert-runpath-file",
+        runpathfilter="realization-3"
+    )
+    assert len(ens) == 1
+    assert ens[3].index == 3
     os.chdir(cwd)
 
 
diff --git a/tests/test_ensembleset.py b/tests/test_ensembleset.py
index f019fc96..6b6b4e46 100644
--- a/tests/test_ensembleset.py
+++ b/tests/test_ensembleset.py
@@ -51,6 +51,13 @@ def symlink_iter(origensdir, newitername):
                 fullpathrealizationdir + "/iter-0", realizationdir + "/" + newitername
             )
 
+def rms_vol2df(kwargs):
+    """Callback function to be sent to ensemble objects"""
+    fullpath = os.path.join(kwargs["realization"].runpath(), kwargs["filename"])
+    # The supplied callback should not fail too easy.
+    if os.path.exists(fullpath):
+        return volumetrics.rmsvolumetrics_txt2df(fullpath)
+    return pd.DataFrame()
 
 def test_ensembleset_reek001(tmpdir):
     """Test import of a stripped 5 realization ensemble,
@@ -211,15 +218,7 @@ def test_ensembleset_reek001(tmpdir):
     assert len(ensset3.keys()) == predel_len - 1
 
     # Test callback functionality, that we can convert rms
-    # volumetrics in each realization. First we need a
-    # wrapper which is able to work on ScratchRealizations.
-    def rms_vol2df(kwargs):
-        """Callback function to be sent to ensemble objects"""
-        fullpath = os.path.join(kwargs["realization"].runpath(), kwargs["filename"])
-        # The supplied callback should not fail too easy.
-        if os.path.exists(fullpath):
-            return volumetrics.rmsvolumetrics_txt2df(fullpath)
-        return pd.DataFrame()
+    # volumetrics in each realization.
 
     if not SKIP_FMU_TOOLS:
         rmsvols_df = ensset3.apply(