diff --git a/numpy/core/_internal.py b/numpy/core/_internal.py
index b0ea603e12a4..7276c45b7327 100644
--- a/numpy/core/_internal.py
+++ b/numpy/core/_internal.py
@@ -8,7 +8,6 @@
 
 import re
 import sys
-import platform
 
 from numpy.compat import unicode
 from .multiarray import dtype, array, ndarray
@@ -17,7 +16,7 @@
 except ImportError:
     ctypes = None
 
-IS_PYPY = platform.python_implementation() == 'PyPy'
+IS_PYPY = 'PyPy' in sys.version
 
 if (sys.byteorder == 'little'):
     _nbo = b'<'
diff --git a/numpy/random/bit_generator.pyx b/numpy/random/bit_generator.pyx
index eb608af6cf69..c8bea9932c0e 100644
--- a/numpy/random/bit_generator.pyx
+++ b/numpy/random/bit_generator.pyx
@@ -44,7 +44,9 @@ except ImportError:
     randbits = SystemRandom().getrandbits
 
 try:
-    from threading import Lock
+    # Threading isn't the cheapest import. Import from the lightweight
+    # _thread module,
+    from _thread import allocate_lock as Lock
 except ImportError:
     from dummy_threading import Lock