How much faster is optimize_for = SPEED?

[jcready]

The section discussing the tradeoffs between setting optimize_for to SPEED or CODE_SIZE give some pretty detailed benchmarks showing the difference in bundle size, but there's only an off-hand comment about the difference in speed:

a small gain in performance for the cost of some code size

And in the next section:

For the Web Browser, it is recommended to use the CODE_SIZE optimization for all messages by setting plugin option --ts_opt optimize_code_size. Then set the file option optimize_for = SPEED for files where you can measure a noticeable performance increase. See code size vs speed for a output size comparison.

How much faster is optimize_for = SPEED?