diff --git a/appveyor.yml b/appveyor.yml
index 11bb01adb..6192aeabe 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -58,32 +58,32 @@ build_script:
   # examples
   - cd %ROOT_DIRECTORY%\examples
   - if defined bjam (
-    b2.exe --hash openssl-version=pre1.1 warnings=all warnings-as-errors=on -j2 %compiler% address-model=%model% picker-debugging=on invariant-checks=full variant=%variant% %linkflags% %include% link=shared crypto=%crypto%
+    b2.exe --hash openssl-version=pre1.1 warnings=all warnings-as-errors=on -j %NUMBER_OF_PROCESSORS% %compiler% address-model=%model% picker-debugging=on invariant-checks=full variant=%variant% %linkflags% %include% link=shared crypto=%crypto%
     )
 
   # tools
   - cd %ROOT_DIRECTORY%\tools
   - if defined bjam (
-    b2.exe --hash openssl-version=pre1.1 warnings=all warnings-as-errors=on -j2 %compiler% address-model=%model% picker-debugging=on invariant-checks=full variant=%variant% %linkflags% %include% link=shared crypto=%crypto%
+    b2.exe --hash openssl-version=pre1.1 warnings=all warnings-as-errors=on -j %NUMBER_OF_PROCESSORS% %compiler% address-model=%model% picker-debugging=on invariant-checks=full variant=%variant% %linkflags% %include% link=shared crypto=%crypto%
     )
 
   # test
   - cd %ROOT_DIRECTORY%\test
   - if defined bjam (
-    b2.exe --hash openssl-version=pre1.1 warnings=all warnings-as-errors=on -j2 %compiler% address-model=%model% picker-debugging=on invariant-checks=full variant=%variant% %linkflags% %include% link=shared crypto=%crypto% win-tests test_upnp test_natpmp testing.execute=off
+    b2.exe --hash openssl-version=pre1.1 warnings=all warnings-as-errors=on -j %NUMBER_OF_PROCESSORS% %compiler% address-model=%model% picker-debugging=on invariant-checks=full variant=%variant% %linkflags% %include% link=shared crypto=%crypto% win-tests test_upnp test_natpmp testing.execute=off
     )
 
   # python binding
   - cd %ROOT_DIRECTORY%\bindings\python
   # we use 64 bit python builds
   - if defined python (
-    b2.exe --hash openssl-version=pre1.1 warnings=all warnings-as-errors=on -j2 %compiler% address-model=%model% picker-debugging=on invariant-checks=full variant=%variant% %linkflags% %include% link=shared crypto=%crypto% libtorrent-link=shared stage_module stage_dependencies
+    b2.exe --hash openssl-version=pre1.1 warnings=all warnings-as-errors=on -j %NUMBER_OF_PROCESSORS% %compiler% address-model=%model% picker-debugging=on invariant-checks=full variant=%variant% %linkflags% %include% link=shared crypto=%crypto% libtorrent-link=shared stage_module stage_dependencies
     )
 
   # simulations
   - cd %ROOT_DIRECTORY%\simulation
   - if defined sim (
-    b2.exe --hash openssl-version=pre1.1 warnings=all warnings-as-errors=on -j2 %compiler% address-model=%model% debug-iterators=off picker-debugging=on invariant-checks=full test_debug %linkflags% %include% boost-link=default link=static crypto=built-in define=BOOST_ASIO_DISABLE_IOCP testing.execute=off
+    b2.exe --hash openssl-version=pre1.1 warnings=all warnings-as-errors=on -j %NUMBER_OF_PROCESSORS% %compiler% address-model=%model% debug-iterators=off picker-debugging=on invariant-checks=full test_debug %linkflags% %include% boost-link=default link=static crypto=built-in define=BOOST_ASIO_DISABLE_IOCP testing.execute=off
     )
 
   # minimal support for cmake build
@@ -98,7 +98,7 @@ build_script:
 test_script:
   - cd %ROOT_DIRECTORY%\test
   - if defined bjam (
-    appveyor-retry b2.exe -l400 --hash openssl-version=pre1.1 warnings=all warnings-as-errors=on -j2 %compiler% address-model=%model% picker-debugging=on invariant-checks=full variant=%variant% %linkflags% %include% link=shared crypto=%crypto% win-tests
+    appveyor-retry b2.exe -l400 --hash openssl-version=pre1.1 warnings=all warnings-as-errors=on -j %NUMBER_OF_PROCESSORS% %compiler% address-model=%model% picker-debugging=on invariant-checks=full variant=%variant% %linkflags% %include% link=shared crypto=%crypto% win-tests
     )
 
   - cd %ROOT_DIRECTORY%\bindings\python
@@ -121,5 +121,5 @@ test_script:
   # certain unexpected terminations (through exceptions)
   - cd %ROOT_DIRECTORY%\simulation
   - if defined sim (
-    b2.exe --hash openssl-version=pre1.1 warnings-as-errors=on -j2 %compiler% address-model=%model% debug-iterators=off picker-debugging=on invariant-checks=full test_debug %linkflags% %include% boost-link=default link=static crypto=built-in define=BOOST_ASIO_DISABLE_IOCP
+    b2.exe --hash openssl-version=pre1.1 warnings-as-errors=on -j %NUMBER_OF_PROCESSORS% %compiler% address-model=%model% debug-iterators=off picker-debugging=on invariant-checks=full test_debug %linkflags% %include% boost-link=default link=static crypto=built-in define=BOOST_ASIO_DISABLE_IOCP
     )