I finally got around to applying Oren's patch. Nice work, BTW! Here are before-and-after timings for the test program I posted before. This is current CVS, release build, Win98SE, MSVC 6, 866MHz: seconds function before after % speedup -------- ------ ----- --------- fastlocals 2.40 2.39 0 globals_via_load_global 3.27 2.53 29 locals_via_load_name 3.46 2.66 30 globals_via_load_name 4.56 2.82 62 builtins_via_load_global 5.99 4.04 48 builtins_via_load_name 7.12 4.84 47 I only care about the XYZ_load_global times (speeding LOAD_NAME is like speeding multiplication by 1531 <wink>), and these numbers are nice.