diff --git a/pyproject.toml b/pyproject.toml
index 418aebe..47d25e2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -34,7 +34,7 @@ dependencies = [
     "psutil>=5.8.0",
     "resampy>=0.2.2",
     "scipy>=1.7.0",
-    "sympy",
+    "sympy>=1.13.2",
     "tqdm>=4.58.0",
     "vtk>=9.0.1",
 ]
diff --git a/src/python/test/test_sim3d.py b/src/python/test/test_sim3d.py
index dcb1b89..5136165 100644
--- a/src/python/test/test_sim3d.py
+++ b/src/python/test/test_sim3d.py
@@ -3,8 +3,9 @@
 import pathlib
 import subprocess
 
-import pytest
 import numpy as np
+import psutil
+import pytest
 import scipy.io.wavfile as wavfile
 
 from pffdtd.analysis.room_modes import find_nearest
@@ -45,9 +46,16 @@ def _skip_if_native_engine_unavailable(engine):
         pytest.skip("Native engine not available")
 
 
+def _skip_if_not_enough_memory(engine):
+    if engine == "python":
+        if psutil.virtual_memory().available <= 6e9:
+            pytest.skip("Not enough memory")
+
+
 @pytest.mark.parametrize("engine", ["python", "native"])
 def test_sim3d_locate_sound_source(tmp_path, engine):
     _skip_if_native_engine_unavailable(engine)
+    _skip_if_not_enough_memory(engine)
 
     fmin = 20
     fmax = 1000
@@ -146,6 +154,7 @@ def test_sim3d_locate_sound_source(tmp_path, engine):
 @pytest.mark.parametrize("engine", ["python", "native"])
 def test_sim3d_infinite_baffle(tmp_path, engine):
     _skip_if_native_engine_unavailable(engine)
+    _skip_if_not_enough_memory(engine)
 
     fmin = 20
     fmax = 1000
@@ -251,11 +260,12 @@ def test_sim3d_infinite_baffle(tmp_path, engine):
     "size,fmax,ppw,fcc,dx_scale,tolerance",
     [
         ((2.8, 2.076, 1.48), 400, 10.5, False, 2, 3.0),
-        ((3.0, 1.0, 2.0), 800, 7.7, True, 3, 6),
+        ((3.0, 1.0, 2.0), 600, 7.7, True, 3, 6),
     ]
 )
 def test_sim3d_detect_room_modes(tmp_path, engine, size, fmax, ppw, fcc, dx_scale, tolerance):
     _skip_if_native_engine_unavailable(engine)
+    _skip_if_not_enough_memory(engine)
 
     L = size[0]
     W = size[1]