Comment Tests – Parsing
In this test the test code is parsed 100 times for each measurement.
The number of comments varies from 1 to 10000 in increments of 666. Each of the comments is 64 characters long
Looks fairly linear – even for a large number of individual comments. Pretty much as expected. No severe penalty for making lots of comments other than the cost of loading and parsing.
James McParlane's Blog 
On the same machine, Firefox was clocked at ~ 2x the speed of IE. (above)