diff --git a/buildsystem/Makefile.comp.cobra b/buildsystem/Makefile.comp.cobra
index 15a0110c2c46ff0694ff65655270fb36fbc9d306..cae1525095cb76eb7d0f7d55b471589f6db06589 100644
--- a/buildsystem/Makefile.comp.cobra
+++ b/buildsystem/Makefile.comp.cobra
@@ -7,10 +7,4 @@ CPV      =  $(CPP)
 else
 CFLAGS_VECTOR =
 CPV      =  $(CPP)
-endif
-
-ifeq (NUM_THREADS,$(findstring NUM_THREADS,$(CONFIGVARS)))
-OPTIMIZE +=  -fopenmp
-else
-OPTIMIZE +=  -Wno-unknown-pragmas
-endif
+endif
\ No newline at end of file
diff --git a/buildsystem/Makefile.comp.cobraopenmpi b/buildsystem/Makefile.comp.cobraopenmpi
index 2a9430a4dc9abe85cfa9777feb0a63013c2e3079..cb88a67377ccf1c1d3bf721b795e470f4c9efa49 100644
--- a/buildsystem/Makefile.comp.cobraopenmpi
+++ b/buildsystem/Makefile.comp.cobraopenmpi
@@ -7,9 +7,3 @@ else
 CFLAGS_VECTOR =
 CPV      =  $(CPP)
 endif
-
-ifeq (NUM_THREADS,$(findstring NUM_THREADS,$(CONFIGVARS)))
-OPTIMIZE +=  -qopenmp
-else
-OPTIMIZE +=  -Wno-unknown-pragmas
-endif
diff --git a/buildsystem/Makefile.comp.freya b/buildsystem/Makefile.comp.freya
index 15a0110c2c46ff0694ff65655270fb36fbc9d306..cae1525095cb76eb7d0f7d55b471589f6db06589 100644
--- a/buildsystem/Makefile.comp.freya
+++ b/buildsystem/Makefile.comp.freya
@@ -7,10 +7,4 @@ CPV      =  $(CPP)
 else
 CFLAGS_VECTOR =
 CPV      =  $(CPP)
-endif
-
-ifeq (NUM_THREADS,$(findstring NUM_THREADS,$(CONFIGVARS)))
-OPTIMIZE +=  -fopenmp
-else
-OPTIMIZE +=  -Wno-unknown-pragmas
-endif
+endif
\ No newline at end of file
diff --git a/buildsystem/Makefile.comp.freyaopenmpi b/buildsystem/Makefile.comp.freyaopenmpi
index c4c0105565302e9be84e383ddae1c41e50e55817..ae8b58b00d3cc94451018eb2c09d179c0dc468eb 100644
--- a/buildsystem/Makefile.comp.freyaopenmpi
+++ b/buildsystem/Makefile.comp.freyaopenmpi
@@ -8,9 +8,3 @@ else
 CFLAGS_VECTOR =
 CPV      =  $(CPP)
 endif
-
-ifeq (NUM_THREADS,$(findstring NUM_THREADS,$(CONFIGVARS)))
-OPTIMIZE +=  -fopenmp
-else
-OPTIMIZE +=  -Wno-unknown-pragmas
-endif
diff --git a/buildsystem/Makefile.comp.gcc b/buildsystem/Makefile.comp.gcc
index 48e196c166958d635b974cff156cead60c4dcee5..f94bb2fb1c9f6755daec2d285e25cdd5eee8562a 100644
--- a/buildsystem/Makefile.comp.gcc
+++ b/buildsystem/Makefile.comp.gcc
@@ -8,9 +8,3 @@ else
 CFLAGS_VECTOR =
 CPV      =  $(CPP)
 endif
-
-ifeq (NUM_THREADS,$(findstring NUM_THREADS,$(CONFIGVARS)))
-OPTIMIZE +=  -fopenmp
-else
-OPTIMIZE +=  -Wno-unknown-pragmas
-endif
diff --git a/buildsystem/Makefile.comp.gcc-paranoia b/buildsystem/Makefile.comp.gcc-paranoia
index 62a8b5c0165f5493801d16a2b71de8bb0b880947..8801fe7fe17e6c4d0d6a48586800a2a77a89f6ab 100644
--- a/buildsystem/Makefile.comp.gcc-paranoia
+++ b/buildsystem/Makefile.comp.gcc-paranoia
@@ -11,10 +11,4 @@ CPV      =  $(CPP)
 else
 CFLAGS_VECTOR =
 CPV      =  $(CPP)
-endif
-
-ifeq (NUM_THREADS,$(findstring NUM_THREADS,$(CONFIGVARS)))
-OPTIMIZE +=  -fopenmp
-else
-OPTIMIZE +=  -Wno-unknown-pragmas
-endif
+endif
\ No newline at end of file
diff --git a/buildsystem/Makefile.comp.ravenopenmpi b/buildsystem/Makefile.comp.ravenopenmpi
index f9892ce226fb3fd1dd2bef07a5eafed4403f3da7..9d273639fbbcf5258cf840dbb133ce23e7fb4077 100644
--- a/buildsystem/Makefile.comp.ravenopenmpi
+++ b/buildsystem/Makefile.comp.ravenopenmpi
@@ -6,10 +6,4 @@ CPV      =  $(CPP)
 else
 CFLAGS_VECTOR =
 CPV      =  $(CPP)
-endif
-
-ifeq (NUM_THREADS,$(findstring NUM_THREADS,$(CONFIGVARS)))
-OPTIMIZE +=  -qopenmp
-else
-OPTIMIZE +=  -Wno-unknown-pragmas
-endif
+endif
\ No newline at end of file
diff --git a/buildsystem/Makefile.comp.supermuc-ng b/buildsystem/Makefile.comp.supermuc-ng
index 275a8175e21e08ed5c27d0561a4f110ef257a022..9fc27ba6f11473c3af322e7da64a1d4a9cfc3e61 100644
--- a/buildsystem/Makefile.comp.supermuc-ng
+++ b/buildsystem/Makefile.comp.supermuc-ng
@@ -8,10 +8,4 @@ CPV      =  $(CPP)
 else
 CFLAGS_VECTOR = 
 CPV      =  $(CPP)
-endif
-
-ifeq (NUM_THREADS,$(findstring NUM_THREADS,$(CONFIGVARS)))
-OPTIMIZE +=  -fopenmp
-else
-OPTIMIZE +=  -Wno-unknown-pragmas
-endif
+endif
\ No newline at end of file
diff --git a/buildsystem/Makefile.comp.supermuc-ng-gcc b/buildsystem/Makefile.comp.supermuc-ng-gcc
index d3d93121ee7871b8764c0a5d2f56563a6ad0d5a0..22360b893eb05872de0cb96be46472a770d9a2e6 100644
--- a/buildsystem/Makefile.comp.supermuc-ng-gcc
+++ b/buildsystem/Makefile.comp.supermuc-ng-gcc
@@ -8,10 +8,4 @@ CPV      =  $(CPP)
 else
 CFLAGS_VECTOR = 
 CPV      =  $(CPP)
-endif
-
-ifeq (NUM_THREADS,$(findstring NUM_THREADS,$(CONFIGVARS)))
-OPTIMIZE +=  -fopenmp
-else
-OPTIMIZE +=  -Wno-unknown-pragmas
-endif
+endif
\ No newline at end of file
diff --git a/buildsystem/Makefile.comp.supermuc-ng-openmpi b/buildsystem/Makefile.comp.supermuc-ng-openmpi
index d3d93121ee7871b8764c0a5d2f56563a6ad0d5a0..7a0ad5c5761ca1d7786178122adcedd05cfe3dfa 100644
--- a/buildsystem/Makefile.comp.supermuc-ng-openmpi
+++ b/buildsystem/Makefile.comp.supermuc-ng-openmpi
@@ -10,8 +10,3 @@ CFLAGS_VECTOR =
 CPV      =  $(CPP)
 endif
 
-ifeq (NUM_THREADS,$(findstring NUM_THREADS,$(CONFIGVARS)))
-OPTIMIZE +=  -fopenmp
-else
-OPTIMIZE +=  -Wno-unknown-pragmas
-endif
diff --git a/src/pm/pm_periodic.cc b/src/pm/pm_periodic.cc
index 753015f518865409b05ef794ee85d10357205301..1eee5b545b707a43fa3ad62a096d81a87aaafdb7 100644
--- a/src/pm/pm_periodic.cc
+++ b/src/pm/pm_periodic.cc
@@ -61,9 +61,6 @@
  * The non-periodic dimension is selected via the GRAVITY_TALLBOX flag. Also in this case, arbitrarily stretched boxes can
  * be used, and one can use PM_ZOOM_OPTIMIZED and/or FFT_COLUMN_BASED if desired.
  *
- * Much of the code is multi-threaded, so there should be some speed-up if OpenMP is used with NUM_THREADS > 1, but the
- * benefit may be limited because the data transfer steps (which weigh in quite heavily) are not accelerated by this.
- *
  * If eight times the particle load per processor exceeds 2^31 ~ 2 billion, one should activate NUMPART_PER_TASK_LARGE.
  * The code will check this condition and terminate if this is violated, so there should hopefully be no severe risk
  * to accidentally forget this.