diff --git a/pkgs/applications/audio/cdparanoia/default.nix b/pkgs/applications/audio/cdparanoia/default.nix
index e4589bc48887..6fa69beee20e 100644
--- a/pkgs/applications/audio/cdparanoia/default.nix
+++ b/pkgs/applications/audio/cdparanoia/default.nix
@@ -6,8 +6,6 @@ stdenv.mkDerivation {
     url = http://downloads.xiph.org/releases/cdparanoia/cdparanoia-III-alpha9.8.src.tgz;
     md5 = "7218e778b5970a86c958e597f952f193";
   };
-
-  NO_PARALLEL_BUILD_buildPhase = 1;
   
   patches = [./fix.patch];
 
diff --git a/pkgs/applications/version-management/subversion/default.nix b/pkgs/applications/version-management/subversion/default.nix
index 3607d9493864..da7e72669c6c 100644
--- a/pkgs/applications/version-management/subversion/default.nix
+++ b/pkgs/applications/version-management/subversion/default.nix
@@ -74,6 +74,4 @@ stdenv.mkDerivation rec {
     maintainers = [ stdenv.lib.maintainers.eelco ];
     platforms = stdenv.lib.platforms.all;
   };
-
-  NO_PARALLEL_BUILD_installPhase = 1;
 }
diff --git a/pkgs/desktops/gnome-2.28/desktop/gnome-doc-utils/default.nix b/pkgs/desktops/gnome-2.28/desktop/gnome-doc-utils/default.nix
index 8b88b6f648e9..c2e49deb009e 100644
--- a/pkgs/desktops/gnome-2.28/desktop/gnome-doc-utils/default.nix
+++ b/pkgs/desktops/gnome-2.28/desktop/gnome-doc-utils/default.nix
@@ -14,6 +14,4 @@ stdenv.mkDerivation {
     wrapProgram $out/bin/xml2po --prefix PYTHONPATH : $(toPythonPath $out) \
       ''${PYTHONPATH:+ --prefix PYTHONPATH : $PYTHONPATH} \
   '';
-
-  NO_PARALLEL_BUILD_buildPhase = 1;
 }
diff --git a/pkgs/development/compilers/haxe/default.nix b/pkgs/development/compilers/haxe/default.nix
index 098e82861b3f..33260cd5469a 100644
--- a/pkgs/development/compilers/haxe/default.nix
+++ b/pkgs/development/compilers/haxe/default.nix
@@ -55,8 +55,6 @@ let
 
       inherit zlib;
 
-      NUM_CORES = 1;
-
       buildPhase = ''
         set -x
         mkdir -p ocaml/{swflib,extc,extlib-dev,xml-light} neko/libs
diff --git a/pkgs/development/compilers/neko/default.nix b/pkgs/development/compilers/neko/default.nix
index 505a7c3256a0..ee8474947f85 100644
--- a/pkgs/development/compilers/neko/default.nix
+++ b/pkgs/development/compilers/neko/default.nix
@@ -70,7 +70,4 @@ composableDerivation {} ( fixed : {
 
   # TODO make them optional and make them work 
   patches = [ ./disable-modules.patch ];
-
-  NUM_CORES = 1;
-
 })
diff --git a/pkgs/development/compilers/ocaml/3.08.0.nix b/pkgs/development/compilers/ocaml/3.08.0.nix
index 1625e4c55346..b2e7e131a817 100644
--- a/pkgs/development/compilers/ocaml/3.08.0.nix
+++ b/pkgs/development/compilers/ocaml/3.08.0.nix
@@ -7,7 +7,6 @@ stdenv.mkDerivation {
     url = http://nixos.org/tarballs/ocaml-3.08.0.tar.gz;
     md5 = "c6ef478362295c150101cdd2efcd38e0";
   };
-  NUM_CORES = 1; # both fail: build and install
   configureScript = ./configure-3.08.0;
   dontAddPrefix = "True";
   configureFlags = ["-no-tk" "-x11lib" x11];
diff --git a/pkgs/development/compilers/ocaml/3.09.1.nix b/pkgs/development/compilers/ocaml/3.09.1.nix
index 9c5f7b288cee..6e9922ccc366 100644
--- a/pkgs/development/compilers/ocaml/3.09.1.nix
+++ b/pkgs/development/compilers/ocaml/3.09.1.nix
@@ -7,7 +7,6 @@ stdenv.mkDerivation {
     url = http://caml.inria.fr/pub/distrib/ocaml-3.09/ocaml-3.09.1.tar.gz;
     md5 = "c73f4b093e27ba5bf13d62923f89befc";
   };
-  NUM_CORES = 1; # both fail: build and install
   configureScript = ./configure-3.09.1;
   dontAddPrefix = "True";
   configureFlags = ["-no-tk" "-x11lib" x11];
diff --git a/pkgs/development/compilers/ocaml/3.10.0.nix b/pkgs/development/compilers/ocaml/3.10.0.nix
index bc92ab1b6897..8a8ddd7ee975 100644
--- a/pkgs/development/compilers/ocaml/3.10.0.nix
+++ b/pkgs/development/compilers/ocaml/3.10.0.nix
@@ -9,8 +9,6 @@ stdenv.mkDerivation (rec {
     sha256 = "1ihmx1civ78s7k2hfc05z1s9vbyx2qw7fg8lnbxnfd6zxkk8878d";
   };
 
-  NUM_CORES = 1; # both fail: build and install
-
   prefixKey = "-prefix ";
   configureFlags = ["-no-tk" "-x11lib" x11];
   buildFlags = "world bootstrap world.opt";
diff --git a/pkgs/development/compilers/ocaml/3.11.1.nix b/pkgs/development/compilers/ocaml/3.11.1.nix
index 901928ec125f..c825830e43d9 100644
--- a/pkgs/development/compilers/ocaml/3.11.1.nix
+++ b/pkgs/development/compilers/ocaml/3.11.1.nix
@@ -14,8 +14,6 @@ stdenv.mkDerivation (rec {
     sha256 = "8c36a28106d4b683a15c547dfe4cb757a53fa9247579d1cc25bd06a22cc62e50";
   };
 
-  NUM_CORES = 1; # both fail: build and install
-
   prefixKey = "-prefix ";
   configureFlags = ["-no-tk"] ++ optionals useX11 [ "-x11lib" x11 ];
   buildFlags = "world" + optionalString useNativeCompilers " bootstrap world.opt";
diff --git a/pkgs/development/libraries/gobject-introspection/default.nix b/pkgs/development/libraries/gobject-introspection/default.nix
index 1c82284783a0..f5fed1e16049 100644
--- a/pkgs/development/libraries/gobject-introspection/default.nix
+++ b/pkgs/development/libraries/gobject-introspection/default.nix
@@ -8,8 +8,6 @@ in
 stdenv.mkDerivation rec {
   name = "${baseName}-${v}";
 
-  NO_PARALLEL_BUILD_buildPhase = 1;
-
   buildInputs = [ flex bison glib pkgconfig python cairo ];
   propagatedBuildInputs = [ libffi ];
   configureFlags = "--enable-gcov";
diff --git a/pkgs/development/libraries/nss/default.nix b/pkgs/development/libraries/nss/default.nix
index 2d1c967e692e..a51c355b6448 100644
--- a/pkgs/development/libraries/nss/default.nix
+++ b/pkgs/development/libraries/nss/default.nix
@@ -19,8 +19,6 @@ stdenv.mkDerivation {
 
   buildInputs = [nspr perl zlib];
 
-  NO_PARALLEL_BUILD_buildPhase = 1;
-
   # Based on the build instructions at
   # http://www.mozilla.org/projects/security/pki/nss/nss-3.11.4/nss-3.11.4-build.html
   
diff --git a/pkgs/development/libraries/openssl/1.x.nix b/pkgs/development/libraries/openssl/1.x.nix
index c64baa17431f..eae32de30e48 100644
--- a/pkgs/development/libraries/openssl/1.x.nix
+++ b/pkgs/development/libraries/openssl/1.x.nix
@@ -14,8 +14,6 @@ stdenv.mkDerivation (rec {
     sha1 = "3f800ea9fa3da1c0f576d689be7dca3d55a4cb62";
   };
 
-  NO_PARALLEL_BUILD_buildPhase = 1;
-
   buildNativeInputs = [ perl ];
 
   configureScript = "./config";
diff --git a/pkgs/development/libraries/openssl/default.nix b/pkgs/development/libraries/openssl/default.nix
index 556b5079ea0d..4e567cf6577b 100644
--- a/pkgs/development/libraries/openssl/default.nix
+++ b/pkgs/development/libraries/openssl/default.nix
@@ -14,8 +14,6 @@ stdenv.mkDerivation ( rec {
     sha256 = "008z1h09pa6dfxs4wgbqj5i1clw4v82b1waqvwanb1kb6wlbq6mh";
   };
 
-  NO_PARALLEL_BUILD_buildPhase = 1;
-
   buildNativeInputs = [ perl ];
 
   configureScript = "./config";
diff --git a/pkgs/development/libraries/pth/default.nix b/pkgs/development/libraries/pth/default.nix
index 875123a1c33f..631a76224062 100644
--- a/pkgs/development/libraries/pth/default.nix
+++ b/pkgs/development/libraries/pth/default.nix
@@ -11,7 +11,4 @@ stdenv.mkDerivation rec {
 		description = "The GNU Portable Threads";
 		homepage = http://www.gnu.org/software/pth;
 	};
-
-        NO_PARALLEL_BUILD_buildPhase = 1;
-        NO_PARALLEL_BUILD_installPhase = 1;
 }
diff --git a/pkgs/development/libraries/slang/default.nix b/pkgs/development/libraries/slang/default.nix
index 37ead3fb9eb6..a7db634dbd04 100644
--- a/pkgs/development/libraries/slang/default.nix
+++ b/pkgs/development/libraries/slang/default.nix
@@ -14,5 +14,4 @@ stdenv.mkDerivation {
   '';
   configureFlags = "--with-png=${libpng} --with-z=${zlib} --with-pcre=${pcre} --with-readline=${readline}";
   buildInputs = [ncurses pcre libpng zlib readline];
-  NO_PARALLEL_BUILD_installPhase = 1;
 }
diff --git a/pkgs/development/tools/parsing/flex/flex-2.5.33.nix b/pkgs/development/tools/parsing/flex/flex-2.5.33.nix
index 18ae038c8cfb..9be98689aeaa 100644
--- a/pkgs/development/tools/parsing/flex/flex-2.5.33.nix
+++ b/pkgs/development/tools/parsing/flex/flex-2.5.33.nix
@@ -17,5 +17,4 @@ stdenv.mkDerivation {
   meta = {
     description = "A fast lexical analyser generator";
   };
-  NO_PARALLEL_BUILD_installPhase = 1;
 }
diff --git a/pkgs/development/tools/parsing/flex/flex-2.5.34.nix b/pkgs/development/tools/parsing/flex/flex-2.5.34.nix
index d5a409a062c9..d56cf0c88a2e 100644
--- a/pkgs/development/tools/parsing/flex/flex-2.5.34.nix
+++ b/pkgs/development/tools/parsing/flex/flex-2.5.34.nix
@@ -16,5 +16,4 @@ stdenv.mkDerivation {
   meta = {
     description = "A fast lexical analyser generator";
   };
-  NO_PARALLEL_BUILD_installPhase = 1;
 }
diff --git a/pkgs/development/tools/parsing/flex/flex-2.5.35.nix b/pkgs/development/tools/parsing/flex/flex-2.5.35.nix
index b9fe7e28cda0..c200e4e7d2f7 100644
--- a/pkgs/development/tools/parsing/flex/flex-2.5.35.nix
+++ b/pkgs/development/tools/parsing/flex/flex-2.5.35.nix
@@ -16,5 +16,4 @@ stdenv.mkDerivation {
   meta = {
     description = "A fast lexical analyser generator";
   };
-  NO_PARALLEL_BUILD_installPhase = 1;
 }
diff --git a/pkgs/development/tools/parsing/flex/flex-2.5.4a.nix b/pkgs/development/tools/parsing/flex/flex-2.5.4a.nix
index bca60808600c..13bb68349790 100644
--- a/pkgs/development/tools/parsing/flex/flex-2.5.4a.nix
+++ b/pkgs/development/tools/parsing/flex/flex-2.5.4a.nix
@@ -9,5 +9,4 @@ stdenv.mkDerivation {
     md5 = "bd8753d0b22e1f4ec87a553a73021adf";
   };
   buildInputs = [yacc];
-  NO_PARALLEL_BUILD_installPhase = 1;
 }
diff --git a/pkgs/stdenv/generic/setup.sh b/pkgs/stdenv/generic/setup.sh
index 5a92f2d33bf8..5e2fc7b24dbe 100644
--- a/pkgs/stdenv/generic/setup.sh
+++ b/pkgs/stdenv/generic/setup.sh
@@ -73,25 +73,6 @@ addToSearchPath() {
     addToSearchPathWithCustomDelimiter "${PATH_DELIMITER}" "$@"
 }
 
-cmd(){
-  echo "cmd: $@"
-  "$@"
-}
-
-runMake(){
-  local optout=NO_PARALLEL_BUILD_${curPhase}
-  [ -n "${!optout}" ] || \
-    local j="$makeFlagsParallelBuild"
-  cmd make ${makefile:+-f $makefile} "$@" $j
-}
-
-######################################################################
-# parallel builds: opt-out
-# - in a phase:     set NO_PARALLEL_BUILD_${PHASE_NAME}
-# - for this build: pass NUM_CORES=1 to the builder
-if [ "$NUM_CORES" != 1 ]; then
-  makeFlagsParallelBuild="-j ${NIX_MAX_PARALLELIZATION:-1} ${NIX_TARGET_LOAD:+-l} $NIX_TARGET_LOAD"
-fi
 
 ######################################################################
 # Initialisation.
@@ -620,7 +601,9 @@ buildPhase() {
         return
     fi
 
-    runMake $makeFlags "${makeFlagsArray[@]}" \
+    echo "make flags: $makeFlags ${makeFlagsArray[@]} $buildFlags ${buildFlagsArray[@]}"
+    make ${makefile:+-f $makefile} \
+        $makeFlags "${makeFlagsArray[@]}" \
         $buildFlags "${buildFlagsArray[@]}"
 
     runHook postBuild
@@ -630,7 +613,9 @@ buildPhase() {
 checkPhase() {
     runHook preCheck
 
-    runMake $makeFlags "${makeFlagsArray[@]}" \
+    echo "check flags: $makeFlags ${makeFlagsArray[@]} $checkFlags ${checkFlagsArray[@]}"
+    make ${makefile:+-f $makefile} \
+        $makeFlags "${makeFlagsArray[@]}" \
         $checkFlags "${checkFlagsArray[@]}" ${checkTarget:-check}
 
     runHook postCheck
@@ -678,7 +663,8 @@ installPhase() {
     ensureDir "$prefix"
 
     installTargets=${installTargets:-install}
-    runMake $installTargets \
+    echo "install flags: $installTargets $makeFlags ${makeFlagsArray[@]} $installFlags ${installFlagsArray[@]}"
+    make ${makefile:+-f $makefile} $installTargets \
         $makeFlags "${makeFlagsArray[@]}" \
         $installFlags "${installFlagsArray[@]}"
 
@@ -754,7 +740,8 @@ fixupPhase() {
 distPhase() {
     runHook preDist
 
-    runMake $distFlags "${distFlagsArray[@]}" ${distTarget:-dist}
+    echo "dist flags: $distFlags ${distFlagsArray[@]}"
+    make ${makefile:+-f $makefile} $distFlags "${distFlagsArray[@]}" ${distTarget:-dist}
 
     if test "$dontCopyDist" != 1; then
         ensureDir "$out/tarballs"
diff --git a/pkgs/tools/graphics/pstoedit/default.nix b/pkgs/tools/graphics/pstoedit/default.nix
index 703811e6bfe1..6f4a41d24251 100644
--- a/pkgs/tools/graphics/pstoedit/default.nix
+++ b/pkgs/tools/graphics/pstoedit/default.nix
@@ -17,6 +17,4 @@ stdenv.mkDerivation {
     platforms = args.lib.platforms.linux;
   };
 
-  NUM_CORES = 1;
-
 }
diff --git a/pkgs/tools/package-management/nix/num-cores.patch b/pkgs/tools/package-management/nix/num-cores.patch
deleted file mode 100644
index 1b82631bd30d..000000000000
--- a/pkgs/tools/package-management/nix/num-cores.patch
+++ /dev/null
@@ -1,31 +0,0 @@
-commit b77e3721f19b4e5084125eb8dc7186117004dd4b
-Author: Marc Weber <marco-oweber@gmx.de>
-Date:   Sun Jun 13 23:53:46 2010 +0200
-
-    generic/setup.sh: add -j (+1) -l (*2) options to make depending on $NUM_CORES
-
-diff --git a/pkgs/stdenv/generic/setup.sh b/pkgs/stdenv/generic/setup.sh
-index a9f4d4d..685c0ec 100644
---- a/pkgs/stdenv/generic/setup.sh
-+++ b/pkgs/stdenv/generic/setup.sh
-@@ -79,9 +79,19 @@ cmd(){
- }
- 
- runMake(){
--  cmd make ${makefile:+-f $makefile} "$@"
-+  local optout=NO_PARALLEL_BUILD_${curPhase}
-+  [ -n "${!optout}" ] || \
-+    local j="$makeFlagsParallelBuild"
-+  cmd make ${makefile:+-f $makefile} "$@" $j
- }
- 
-+######################################################################
-+# parallel builds: opt-out
-+# - in a phase:     set NO_PARALLEL_BUILD_${PHASE_NAME}
-+# - for this build: pass NUM_CORES=1 to the builder
-+if [ "$NUM_CORES" -gt 1 ]; then
-+  makeFlagsParallelBuild="-j $(( $NUM_CORES + 1 )) -l $(( 2 * $NUM_CORES ))"
-+fi
- 
- ######################################################################
- # Initialisation.
diff --git a/pkgs/tools/package-management/nix/unstable.nix b/pkgs/tools/package-management/nix/unstable.nix
index f1c28d17713e..f45172ba426e 100644
--- a/pkgs/tools/package-management/nix/unstable.nix
+++ b/pkgs/tools/package-management/nix/unstable.nix
@@ -40,6 +40,4 @@ stdenv.mkDerivation rec {
     homepage = http://nixos.org/;
     license = "LGPLv2+";
   };
-
-  patches = [ ./num-cores.patch ];
 }
diff --git a/pkgs/top-level/perl-packages.nix b/pkgs/top-level/perl-packages.nix
index b3f3dbca5e61..dadc86907963 100644
--- a/pkgs/top-level/perl-packages.nix
+++ b/pkgs/top-level/perl-packages.nix
@@ -2858,7 +2858,6 @@ rec {
   };
 
   XMLSAX = buildPerlPackage {
-    NUM_CORES=1;
     name = "XML-SAX-0.96";
     src = fetchurl {
       url = mirror://cpan/authors/id/G/GR/GRANTM/XML-SAX-0.96.tar.gz;