diff --git a/boost/Makefile.am b/boost/Makefile.am
index 69198704d9..cfac86b4b9 100644
--- a/boost/Makefile.am
+++ b/boost/Makefile.am
@@ -2,11 +2,6 @@ include $(top_srcdir)/config/common.am
 
 noinst_LIBRARIES = liblyxboost.a
 
-# Using precompiled headers makes compilation >10% slower
-#EXTRA_DIST = pch.h
-#BUILT_SOURCES = $(PCH_FILE)
-#AM_CPPFLAGS += $(PCH_FLAGS)
-
 EXTRA_DIST = boost \
 	CMakeLists.txt \
 	libs/CMakeLists.txt \
diff --git a/boost/pch.h b/boost/pch.h
deleted file mode 100644
index 98436acce5..0000000000
--- a/boost/pch.h
+++ /dev/null
@@ -1,28 +0,0 @@
-#include <boost/config.hpp>
-#include <boost/detail/workaround.hpp>
-#include <boost/scoped_array.hpp>
-#include <boost/signals/connection.hpp>
-#include <boost/signals/detail/signal_base.hpp>
-#include <boost/signals/slot.hpp>
-#include <boost/signals/trackable.hpp>
-#include <boost/throw_exception.hpp>
-
-#include <algorithm>
-#include <cassert>
-#include <cctype>
-#include <cerrno>
-#include <climits>
-#include <clocale>
-#include <cwchar>
-#include <iostream>
-#include <list>
-#include <locale>
-#include <map>
-#include <new>
-#include <ostream>
-#include <set>
-#include <stdexcept>
-#include <string>
-#include <vector>
-
-#include <sys/stat.h>  // last_write_time() uses stat()
diff --git a/config/common.am b/config/common.am
index cabc35a4c0..e87279b115 100644
--- a/config/common.am
+++ b/config/common.am
@@ -1,6 +1,4 @@
-CLEANFILES = pch.h.gch
-
-DISTCLEANFILES= pch.h.gch.dep *.orig *.rej *~ *.bak core
+DISTCLEANFILES= *.orig *.rej *~ *.bak core
 
 MAINTAINERCLEANFILES = $(srcdir)/Makefile.in
 
@@ -8,24 +6,4 @@ AM_INSTALL_DATA_FLAGS = $(INSTALL) -m 644 -D
 
 AM_ETAGSFLAGS = --lang=c++
 
-if LYX_BUILD_PCH
-PCH_SOURCE = $(srcdir)/pch.h
-PCH_FLAGS = -Winvalid-pch --include=$(PCH_SOURCE)
-PCH_FILE = ./pch.h.gch
-sinclude ./pch.h.gch.dep
-
-*.o *.lo *.obj: $(PCH_FILE)
-
-$(PCH_FILE): $(PCH_SOURCE)
-	$(MAKE) PCH_FLAGS= pch-file
-
-pch-file:
-	$(CXXCOMPILE) -x c++-header -fPIC -DPIC $(PCH_SOURCE) -o $(PCH_FILE) \
-	-MT $(PCH_FILE)  -MD -MP -MF "./$(PCH_FILE).Tdep" \
-	&& mv "./$(PCH_FILE).Tdep" "./$(PCH_FILE).dep" \
-	|| rm "./$(PCH_FILE).Tdep"
-endif
-
-SUFFIXES = .gch
-
 LIBS =
diff --git a/config/lyxinclude.m4 b/config/lyxinclude.m4
index 13fe0b5414..275e2e8661 100644
--- a/config/lyxinclude.m4
+++ b/config/lyxinclude.m4
@@ -263,11 +263,6 @@ case $enable_optimization in
     *) lyx_optim=${enable_optimization};;
 esac
 
-AC_ARG_ENABLE(pch,
-  AC_HELP_STRING([--enable-pch],[enable precompiled headers]),,
-	enable_pch=no;)
-lyx_pch_comp=no
-
 AC_ARG_ENABLE(cxx11,
   AC_HELP_STRING([--disable-cxx11],[disable C++11 mode (default: enabled for known good compilers)]),,
   enable_cxx11=auto;)
@@ -316,7 +311,6 @@ if test x$GXX = xyes; then
   fi
   case $gxx_version in
       2.*|3.*) AC_ERROR([gcc 4.x is required]);;
-      *)  test $enable_pch = yes && lyx_pch_comp=yes ;;
   esac
   if test x$enable_stdlib_debug = xyes ; then
     dnl FIXME: for clang/libc++, one should define _LIBCPP_DEBUG2=0
@@ -381,8 +375,6 @@ if test x$GXX = xyes; then
   fi
 fi
 AM_CONDITIONAL([LYX_USE_STD_REGEX], test $lyx_std_regex = yes)
-test "$lyx_pch_comp" = yes && lyx_flags="$lyx_flags pch"
-AM_CONDITIONAL(LYX_BUILD_PCH, test "$lyx_pch_comp" = yes)
 ])dnl
 
 dnl Usage: LYX_USE_INCLUDED_BOOST : select if the included boost should
diff --git a/development/cygwin/Makefile.am b/development/cygwin/Makefile.am
index 6e5684f944..e313415359 100644
--- a/development/cygwin/Makefile.am
+++ b/development/cygwin/Makefile.am
@@ -19,7 +19,7 @@ lyxwin_SOURCES = lyxwin.c lyxwinres.rc
 lyxeditor_LDFLAGS=-mwindows -e _mainCRTStartup
 lyxwin_LDFLAGS=-mwindows -e _mainCRTStartup
 
-CLEANFILES += lyxeditor.sh lyx_32x32.ico lyx_doc_32x32.ico
+CLEANFILES = lyxeditor.sh lyx_32x32.ico lyx_doc_32x32.ico
 
 lyxeditor.sh:
 	cp $(top_srcdir)/development/tools/lyxeditor $@
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 4dbed89463..5586af32ce 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -12,7 +12,7 @@ dist_pkgdata_DATA = CREDITS autocorrect chkconfig.ltx external_templates \
 
 # We use DATA now instead of PYTHON because automake 1.11.2 complains.
 # Note that we "chmod 755" manually this file in install-data-hook.
-dist_pkgdata_DATA += configure.py 
+dist_pkgdata_DATA += configure.py
 
 dist_noinst_DATA = \
 	appdata.xml \
@@ -260,7 +260,7 @@ dist_springerexamples_DATA = \
 	examples/springer/svmult_part.lyx \
 	examples/springer/svmult_preface.lyx \
 	examples/springer/svmult_referenc.lyx
-	
+
 thesisexamplesdir = $(pkgdatadir)/examples/thesis
 dist_thesisexamples_DATA = \
 	examples/thesis/Acknowledgments.lyx \
@@ -1915,7 +1915,7 @@ dist_imagesclassic_DATA = \
 	images/classic/view-others.png
 
 imagescommandsdir = $(imagesdir)/commands
-dist_imagescommands_DATA = 
+dist_imagescommands_DATA =
 
 kbddir = $(pkgdatadir)/kbd
 dist_kbd_DATA = \
@@ -2309,8 +2309,8 @@ lyx@program_suffix@.desktop: lyx.desktop-temp
 desktopdir = $(datadir)/applications
 desktop_DATA = lyx@program_suffix@.desktop
 
-CLEANFILES += lyx@program_suffix@.desktop lyx.desktop-temp \
-              lyx@program_suffix@.svg lyx@program_suffix@.png
+CLEANFILES = lyx@program_suffix@.desktop lyx.desktop-temp \
+             lyx@program_suffix@.svg lyx@program_suffix@.png
 endif
 dist_noinst_DATA += lyx.desktop.in images/lyx.svg images/lyx.png
 
diff --git a/lib/lyx2lyx/Makefile.am b/lib/lyx2lyx/Makefile.am
index ace1d72bc3..4490cb72f3 100644
--- a/lib/lyx2lyx/Makefile.am
+++ b/lib/lyx2lyx/Makefile.am
@@ -1,6 +1,6 @@
 include $(top_srcdir)/config/common.am
 
-CLEANFILES += *.pyc *.pyo
+CLEANFILES = *.pyc *.pyo
 
 EXTRA_DIST = lyx2lyx_version.py.in test_parser_tools.py CMakeLists.txt
 
diff --git a/src/Makefile.am b/src/Makefile.am
index 35d890f709..1ebf6c21e9 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -2,7 +2,7 @@ include $(top_srcdir)/config/common.am
 
 ############################### Core  ##############################
 
-AM_CPPFLAGS += $(PCH_FLAGS) -I$(top_srcdir)/src $(BOOST_INCLUDES) $(ENCHANT_CFLAGS) $(HUNSPELL_CFLAGS)
+AM_CPPFLAGS += -I$(top_srcdir)/src $(BOOST_INCLUDES) $(ENCHANT_CFLAGS) $(HUNSPELL_CFLAGS)
 AM_CPPFLAGS += $(QT_CPPFLAGS) $(QT_CORE_INCLUDES)
 
 if BUILD_CLIENT_SUBDIR
@@ -12,7 +12,6 @@ endif
 SUBDIRS = support frontends . $(CLIENT) tex2lyx
 
 EXTRA_DIST = lyx_commit_hash.h.in \
-	pch.h \
 	CMakeLists.txt \
 	graphics/CMakeLists.txt \
 	insets/CMakeLists.txt \
@@ -51,8 +50,6 @@ endif
 
 #lyx_LDFLAGS=-Wl,-O1
 
-BUILT_SOURCES = $(PCH_FILE)
-
 if INSTALL_MACOSX
 APPLESPELL = AppleSpellChecker.cpp AppleSpellChecker.h
 endif
@@ -324,8 +321,8 @@ update_commit_hash:
 
 lyx_commit_hash.h: update_commit_hash
 
-BUILT_SOURCES += lyx_commit_hash.h
-CLEANFILES += lyx_commit_hash.h
+BUILT_SOURCES = lyx_commit_hash.h
+CLEANFILES = lyx_commit_hash.h
 
 lyxcore.cpp:
 	@echo -e '$(SOURCEFILESCORE:%=\n#include "%")\n' > $@
diff --git a/src/client/Makefile.am b/src/client/Makefile.am
index d652f0f696..83c31265b5 100644
--- a/src/client/Makefile.am
+++ b/src/client/Makefile.am
@@ -1,6 +1,6 @@
 include $(top_srcdir)/config/common.am
 
-CLEANFILES += $(man_MANS)
+CLEANFILES = $(man_MANS)
 
 man_MANS = lyxclient.1
 
@@ -31,7 +31,7 @@ SOURCEFILES = \
   boost.cpp \
   client.cpp
 
-HEADERFILES = 
+HEADERFILES =
 
 
 lyxclient.cpp:
@@ -47,10 +47,6 @@ lyxclient_SOURCES = lyxclient.cpp $(HEADERFILES)
 
 else
 
-EXTRA_DIST += pch.h
-AM_CPPFLAGS += $(PCH_FLAGS)
-BUILT_SOURCES = $(PCH_FILE)
-
 lyxclient_SOURCES = $(SOURCEFILES) $(HEADERFILES)
 
 endif
diff --git a/src/client/pch.h b/src/client/pch.h
deleted file mode 100644
index 43926f7a14..0000000000
--- a/src/client/pch.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#include <config.h>
-
-#include <cerrno>
-#include <cstdlib>
-#include <exception>
-#include <iomanip>
-#include <iostream>
-#include <map>
-#include <string>
-#include <vector>
diff --git a/src/frontends/qt4/Makefile.am b/src/frontends/qt4/Makefile.am
index e4d7e22f34..8fe26a1aee 100644
--- a/src/frontends/qt4/Makefile.am
+++ b/src/frontends/qt4/Makefile.am
@@ -4,7 +4,7 @@ BUILT_SOURCES = $(UIFILES:%.ui=ui_%.h)
 BUILT_SOURCES += $(MOCEDFILES)
 BUILT_SOURCES += Resources.cpp Resources.qrc
 
-CLEANFILES += $(BUILT_SOURCES)
+CLEANFILES = $(BUILT_SOURCES)
 
 #########################  Qt stuff  #############################
 # Use _() for localization instead of tr() or trUtf8()
@@ -374,9 +374,6 @@ liblyxqt4_a_SOURCES = \
 	$(MOCHEADER) \
 	$(NOMOCHEADER)
 
-EXTRA_DIST = pch.h CMakeLists.txt $(UIFILES:%=ui/%)
-BUILT_SOURCES += $(PCH_FILE)
-AM_CPPFLAGS += $(PCH_FLAGS)
-
+EXTRA_DIST = CMakeLists.txt $(UIFILES:%=ui/%)
 
 endif
diff --git a/src/frontends/qt4/pch.h b/src/frontends/qt4/pch.h
deleted file mode 100644
index 3f7b1d8005..0000000000
--- a/src/frontends/qt4/pch.h
+++ /dev/null
@@ -1,16 +0,0 @@
-// -*- C++ -*-
-
-#include <config.h>
-
-#include <algorithm>
-#include <cmath>
-#include <iomanip>
-#include <map>
-#include <sstream>
-#include <stack>
-#include <string>
-#include <utility>
-#include <vector>
-
-#include <QtCore>
-#include <QtGui>
diff --git a/src/pch.h b/src/pch.h
deleted file mode 100644
index 41bb9e794f..0000000000
--- a/src/pch.h
+++ /dev/null
@@ -1,22 +0,0 @@
-#include <config.h>
-
-#include <algorithm>
-#include <deque>
-#include <exception>
-#include <fstream>
-#include <functional>
-#include <iomanip>
-#include <ios>
-#include <iosfwd>
-#include <iostream>
-#include <iterator>
-#include <list>
-#include <map>
-#include <memory>
-#include <queue>
-#include <set>
-#include <sstream>
-#include <stack>
-#include <string>
-#include <utility>
-#include <vector>
diff --git a/src/support/Makefile.am b/src/support/Makefile.am
index cbd40473f7..ed6af579d1 100644
--- a/src/support/Makefile.am
+++ b/src/support/Makefile.am
@@ -1,14 +1,10 @@
 include $(top_srcdir)/config/common.am
 
-CLEANFILES += $(BUILT_SOURCES)
-
-EXTRA_DIST = pch.h \
-	os_cygwin.cpp os_unix.cpp os_win32.cpp os_win32.h \
+EXTRA_DIST = os_cygwin.cpp os_unix.cpp os_win32.cpp os_win32.h \
 	CMakeLists.txt tests/CMakeLists.txt tests/supporttest.cmake
 
 noinst_LIBRARIES = liblyxsupport.a
 
-BUILT_SOURCES = $(PCH_FILE)
 
 #########################  Qt stuff  #############################
 #
@@ -19,8 +15,8 @@ MOCHEADER = \
 
 MOCEDFILES = $(MOCHEADER:%.h=moc_%.cpp)
 
-CLEANFILES += $(MOCEDFILES)
-BUILT_SOURCES += $(MOCEDFILES)
+CLEANFILES = $(MOCEDFILES)
+BUILT_SOURCES = $(MOCEDFILES)
 
 moc_%.cpp: %.h
 	$(QT_MOC) -o $@ $<
@@ -30,8 +26,7 @@ liblyxsupport_a_DEPENDENCIES = $(MOCEDFILES)
 #
 ##################################################################
 
-AM_CPPFLAGS += $(PCH_FLAGS) -I$(srcdir)/.. $(BOOST_INCLUDES)
-AM_CPPFLAGS += $(QT_CPPFLAGS) $(QT_INCLUDES)
+AM_CPPFLAGS += -I$(srcdir)/.. $(BOOST_INCLUDES) $(QT_CPPFLAGS) $(QT_INCLUDES)
 
 liblyxsupport_a_SOURCES = \
 	FileMonitor.h \
diff --git a/src/support/pch.h b/src/support/pch.h
deleted file mode 100644
index 7a96e19c06..0000000000
--- a/src/support/pch.h
+++ /dev/null
@@ -1,22 +0,0 @@
-#include <config.h>
-
-#include <algorithm>
-#include <cctype>
-#include <cerrno>
-#include <csignal>
-#include <cstddef>
-#include <cstdio>
-#include <cstdlib>
-#include <ctime>
-#include <fstream>
-#include <functional>
-#include <iostream>
-#include <istream>
-#include <iterator>
-#include <list>
-#include <map>
-#include <ostream>
-#include <sstream>
-#include <string>
-#include <utility>
-#include <vector>
diff --git a/src/tex2lyx/Makefile.am b/src/tex2lyx/Makefile.am
index 45c27202a7..3471d012c5 100644
--- a/src/tex2lyx/Makefile.am
+++ b/src/tex2lyx/Makefile.am
@@ -1,6 +1,6 @@
 include $(top_srcdir)/config/common.am
 
-EXTRA_DIST = TODO.txt tex2lyx.1in $(TEST_FILES) $(TEST_RESULTS) pch.h \
+EXTRA_DIST = TODO.txt tex2lyx.1in $(TEST_FILES) $(TEST_RESULTS) \
 	CMakeLists.txt test/CMakeLists.txt
 
 #noinst_LIBRARIES = libtexparser.a
@@ -17,7 +17,7 @@ bin_PROGRAMS = tex2lyx
 
 DEFAULT_INCLUDES =
 
-AM_CPPFLAGS += $(PCH_FLAGS) -I$(top_srcdir)/src/tex2lyx \
+AM_CPPFLAGS += -I$(top_srcdir)/src/tex2lyx \
 	-I$(top_srcdir)/src -I$(top_builddir) -I$(top_builddir)/src \
 	$(BOOST_INCLUDES)
 
@@ -105,8 +105,6 @@ LINKED_FILES = \
 	../TextClass.cpp \
 	../version.cpp
 
-BUILT_SOURCES = $(PCH_FILE)
-
 tex2lyx_SOURCES = \
 	$(LINKED_FILES) \
 	boost.cpp \
diff --git a/src/tex2lyx/pch.h b/src/tex2lyx/pch.h
deleted file mode 100644
index c00fdacdff..0000000000
--- a/src/tex2lyx/pch.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#include <config.h>
-
-#include <algorithm>
-#include <cstdlib>
-#include <exception>
-#include <fstream>
-#include <iosfwd>
-#include <iostream>
-#include <map>
-#include <sstream>
-#include <string>
-#include <vector>