perf regression in vbench frame_mult in 0.11.0
![frame_mult](https://f.cloud.github.com/assets/1820866/377747/337997f4-a4e8-11e2-8b32-6dc5767dc8e5.png)

6a283f4    28.066921
d2624b5    27.740240
aae6213    31.054401
1c0ed4a    31.372213
36a15ef    31.113815
