The benchmark suite doesn't show any significant speedup or slowdown generally:

Report on Linux fsol 3.8.0-27-generic #40-Ubuntu SMP Tue Jul 9 00:17:05 UTC 2013 x86_64 x86_64
Total CPU cores: 4

### django_v2 ###
Min: 0.672909 -> 0.659464: 1.02x faster
Avg: 0.673821 -> 0.660258: 1.02x faster
Significant (t=32.72)
Stddev: 0.00071 -> 0.00060: 1.1869x smaller

### fastunpickle ###
Min: 0.578535 -> 0.593218: 1.03x slower
Avg: 0.578700 -> 0.593440: 1.03x slower
Significant (t=-185.83)
Stddev: 0.00011 -> 0.00014: 1.1950x larger

### float ###
Min: 0.309679 -> 0.302615: 1.02x faster
Avg: 0.312457 -> 0.304713: 1.03x faster
Significant (t=4.33)
Stddev: 0.00326 -> 0.00232: 1.4039x smaller

### go ###
Min: 0.602035 -> 0.578129: 1.04x faster
Avg: 0.604634 -> 0.581584: 1.04x faster
Significant (t=12.50)
Stddev: 0.00253 -> 0.00325: 1.2855x larger

### nqueens ###
Min: 0.309602 -> 0.316767: 1.02x slower
Avg: 0.310222 -> 0.317734: 1.02x slower
Significant (t=-21.22)
Stddev: 0.00057 -> 0.00055: 1.0295x smaller

### richards ###
Min: 0.184306 -> 0.178887: 1.03x faster
Avg: 0.184969 -> 0.180215: 1.03x faster
Significant (t=8.40)
Stddev: 0.00076 -> 0.00101: 1.3380x larger

### silent_logging ###
Min: 0.080233 -> 0.073160: 1.10x faster
Avg: 0.080594 -> 0.073170: 1.10x faster
Significant (t=69.28)
Stddev: 0.00024 -> 0.00001: 21.7820x smaller

### threaded_count ###
Min: 0.234882 -> 0.226954: 1.03x faster
Avg: 0.241049 -> 0.231458: 1.04x faster
Significant (t=3.04)
Stddev: 0.00567 -> 0.00420: 1.3519x smaller

### unpack_sequence ###
Min: 0.000046 -> 0.000048: 1.05x slower
Avg: 0.000046 -> 0.000049: 1.06x slower
Significant (t=-299.85)
Stddev: 0.00000 -> 0.00000: 1.0256x larger

The following not significant results are hidden, use -v to show them:
call_method, call_method_slots, call_method_unknown, call_simple, chaos, fannkuch, fastpickle, formatted_logging, iterative_count, json_dump_v2, json_load, meteor_contest, nbody, normal_startup, pathlib, pidigits, raytrace, regex_compile, regex_effbot, regex_v8, simple_logging, spectral_norm, startup_nosite, telco.