diff --git a/Lib/test/regrtest.py b/Lib/test/regrtest.py
--- a/Lib/test/regrtest.py
+++ b/Lib/test/regrtest.py
@@ -374,6 +374,12 @@ def main(tests=None, testdir=None, verbo
             forever = True
         elif o in ('-j', '--multiprocess'):
             use_mp = int(a)
+            if use_mp <= 0:
+                try:
+                    import multiprocessing
+                    use_mp = multiprocessing.cpu_count()
+                except (ImportError, NotImplementedError):
+                    use_mp = 3  # safe value even for single-core CPUs
         elif o == '--header':
             header = True
         elif o == '--slaveargs':
diff --git a/Makefile.pre.in b/Makefile.pre.in
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -750,20 +750,18 @@ PYTHON_HEADERS= \
 # generated bytecode.  This is sometimes a very shy bug needing a lot of
 # sample data.
 
-TESTOPTS=	-l $(EXTRATESTOPTS)
-TESTPROG=	$(srcdir)/Lib/test/regrtest.py
+TESTOPTS=	$(EXTRATESTOPTS)
+TESTPROG=	-m test
 TESTPYTHON=	$(RUNSHARED) ./$(BUILDPYTHON) -Wd -E -bb $(TESTPYTHONOPTS)
 test:		all platform
 		-find $(srcdir)/Lib -name '*.py[co]' -print | xargs rm -f
-		-$(TESTPYTHON) $(TESTPROG) $(TESTOPTS)
-		$(TESTPYTHON) $(TESTPROG) $(TESTOPTS)
+		$(TESTPYTHON) $(TESTPROG) -j0 $(TESTOPTS)
 
 testall:	all platform
 		-find $(srcdir)/Lib -name '*.py[co]' -print | xargs rm -f
 		$(TESTPYTHON) $(srcdir)/Lib/compileall.py
 		-find $(srcdir)/Lib -name '*.py[co]' -print | xargs rm -f
-		-$(TESTPYTHON) $(TESTPROG) -uall $(TESTOPTS)
-		$(TESTPYTHON) $(TESTPROG) -uall $(TESTOPTS)
+		$(TESTPYTHON) $(TESTPROG) -j0 -uall $(TESTOPTS)
 
 #  Run the unitests for both architectures in a Universal build on OSX
 #  Must be run on an Intel box.
@@ -773,7 +771,6 @@ testuniversal:	all platform
 			exit 1 ;\
 		fi
 		-find $(srcdir)/Lib -name '*.py[co]' -print | xargs rm -f
-		-$(TESTPYTHON) $(TESTPROG) -uall $(TESTOPTS)
 		$(TESTPYTHON) $(TESTPROG) -uall $(TESTOPTS)
 		$(RUNSHARED) /usr/libexec/oah/translate ./$(BUILDPYTHON) -E $(TESTPROG) -uall $(TESTOPTS)
 
@@ -784,23 +781,7 @@ buildbottest:	all platform
 		-@if which pybuildbot.identify >/dev/null 2>&1; then \
 			pybuildbot.identify "CC='$(CC)'" "CXX='$(CXX)'"; \
 		fi
-		$(TESTPYTHON) $(TESTPROG) -uall -rwW $(TESTOPTS)
-
-QUICKTESTOPTS=	$(TESTOPTS) -x test_subprocess test_io test_lib2to3 \
-		test_multibytecodec test_urllib2_localnet test_itertools \
-		test_multiprocessing test_mailbox test_socket test_poll \
-		test_select test_zipfile
-quicktest:	all platform
-		-find $(srcdir)/Lib -name '*.py[co]' -print | xargs rm -f
-		-$(TESTPYTHON) $(TESTPROG) $(QUICKTESTOPTS)
-		$(TESTPYTHON) $(TESTPROG) $(QUICKTESTOPTS)
-
-MEMTESTOPTS=    $(QUICKTESTOPTS) -x test_dl test___all__ test_fork1 \
-		test_longexp
-memtest:	all platform
-		-rm -f $(srcdir)/Lib/test/*.py[co]
-		-$(TESTPYTHON) $(TESTPROG) $(MEMTESTOPTS)
-		$(TESTPYTHON) $(TESTPROG) $(MEMTESTOPTS)
+		$(TESTPYTHON) $(TESTPROG) -uall -lrwW $(TESTOPTS)
 
 install: altinstall bininstall
 
@@ -1312,7 +1293,7 @@ patchcheck:
 Python/thread.o: @THREADHEADERS@
 
 # Declare targets that aren't real files
-.PHONY: all build_all sharedmods oldsharedmods test quicktest memtest
+.PHONY: all build_all sharedmods oldsharedmods test
 .PHONY: install altinstall oldsharedinstall bininstall altbininstall
 .PHONY: maninstall libinstall inclinstall libainstall sharedinstall
 .PHONY: frameworkinstall frameworkinstallframework frameworkinstallstructure