diff --git a/pkgs/development/libraries/science/math/openblas/default.nix b/pkgs/development/libraries/science/math/openblas/default.nix
index a452037a235e..8dc2b542be75 100644
--- a/pkgs/development/libraries/science/math/openblas/default.nix
+++ b/pkgs/development/libraries/science/math/openblas/default.nix
@@ -1,5 +1,15 @@
 { stdenv, fetchurl, gfortran, perl, liblapack, config }:
 
+# Minimum CPU requirements:
+# x86: Pentium 4 (Prescott, circa 2004)
+# x86_64: Opteron (circa 2003)
+# These are the settings used for the generic builds. Performance will
+# be poor on modern systems. The goal of the Hydra builds is simply to
+# support as many systems as possible. OpenBLAS may support older
+# CPU architectures, but you will need to set 'config.openblas.target'
+# and 'config.openblas.preferLocalBuild', which will build it on your
+# local machine.
+
 let local = config.openblas.preferLocalBuild or false;
     localTarget = config.openblas.target or "";
 in
@@ -20,18 +30,24 @@ stdenv.mkDerivation rec {
   cpu = builtins.head (stdenv.lib.splitString "-" stdenv.system);
 
   target = if local then localTarget else
-    if cpu == "i686" then "P2" else
-    if cpu == "x86_64" then "CORE2" else
+    if cpu == "i686" then "PRESCOTT" else
+    if cpu == "x86_64" then "OPTERON" else
      # allow autodetect
       "";
 
-  makeFlags = "${if target != "" then "TARGET=" else ""}${target} FC=gfortran CC=cc PREFIX=\"\$(out)\" INTERFACE64=1";
+  makeFlags = [
+    "${if target != "" then "TARGET=" else ""}${target}"
+    "FC=gfortran"
+    "CC=gcc"
+    ''PREFIX="''$(out)"''
+    "INTERFACE64=1"
+  ];
 
   meta = with stdenv.lib; {
     description = "Basic Linear Algebra Subprograms";
     license = licenses.bsd3;
     homepage = "https://github.com/xianyi/OpenBLAS";
-    platforms = [ "x86_64-linux" ];
+    platforms = with platforms; linux;
     maintainers = with maintainers; [ ttuegel ];
   };
 }