Yes, today. Chrome 4 is not faster than Chrome 3 but Firefox 3.6 now allows jobs of about 50 structures.
|Browser||max. job size|
Those batch sizes allow for script execution times of about 1 second. The idea behind this is, that this does not interfere with other scripts on a page if the job is running embedded, e.g. in an invisible iframe.
If the page is dedicated, much larger jobs might be possible up to the limit of the browser that triggers the 'A script is not responding' error message.
Update: IE 8.x is twice as fast as IE 6.x, but still slow compared to the competitiors.