diff --git a/ironic_python_agent/hardware.py b/ironic_python_agent/hardware.py
index e15926a5c..97d64162b 100644
--- a/ironic_python_agent/hardware.py
+++ b/ironic_python_agent/hardware.py
@@ -421,7 +421,7 @@ class GenericHardwareManager(HardwareManager):
             total = int(psutil.phymem_usage().total)
 
         try:
-            out, _e = utils.execute("dmidecode --type memory | grep Size",
+            out, _e = utils.execute("dmidecode --type 17 | grep Size",
                                     shell=True)
         except (processutils.ProcessExecutionError, OSError) as e:
             LOG.warning("Cannot get real physical memory size: %s", e)
@@ -433,12 +433,20 @@ class GenericHardwareManager(HardwareManager):
                 if not line:
                     continue
 
+                if 'Size:' not in line:
+                    continue
+
+                value = None
                 try:
-                    value = line.split(None, 1)[1].strip()
+                    value = line.split('Size: ', 1)[1]
                     physical += int(UNIT_CONVERTER(value).to_base_units())
                 except Exception as exc:
-                    LOG.error('Cannot parse size expression %s: %s',
-                              line, exc)
+                    if (value == "No Module Installed" or
+                            value == "Not Installed"):
+                        LOG.debug('One memory slot is empty')
+                    else:
+                        LOG.error('Cannot parse size expression %s: %s',
+                                  line, exc)
 
             if not physical:
                 LOG.warning('failed to get real physical RAM, dmidecode '
diff --git a/ironic_python_agent/tests/unit/test_hardware.py b/ironic_python_agent/tests/unit/test_hardware.py
index f3523da67..c02519e3c 100644
--- a/ironic_python_agent/tests/unit/test_hardware.py
+++ b/ironic_python_agent/tests/unit/test_hardware.py
@@ -421,7 +421,10 @@ class TestGenericHardwareManager(test_base.BaseTestCase):
     def test_get_memory(self, mocked_execute, mocked_usage):
         mocked_usage.return_value = mock.Mock(total=3952 * 1024 * 1024)
         mocked_execute.return_value = (
-            "Foo\nSize: 2048 MB\nSize: 2 GB\n",
+            ("Foo\nSize: 2048 MB\nSize: 2 GB\n"
+             "Installed Size: Not Installed\n"
+             "Enabled Size: Not Installed\n"
+             "Size: No Module Installed\n"),
             ""
         )
 
diff --git a/releasenotes/notes/add-unit-test-cc4a1a05859ad17d.yaml b/releasenotes/notes/add-unit-test-cc4a1a05859ad17d.yaml
new file mode 100644
index 000000000..f4c09eb52
--- /dev/null
+++ b/releasenotes/notes/add-unit-test-cc4a1a05859ad17d.yaml
@@ -0,0 +1,5 @@
+---
+fixes:
+    - dmidecode output produces less parsing errors and logs
+      common and normal output like "No Module Installed" or
+      "Not Installed" in debug instead of error.