Build results page is very slow to generate with large numbers of test failures

The build results page is very slow to generate when there are large numbers of test failures.

We have a build failing with 543 test failures (due to some seriously broken code) - the resulting page is 600k in size, and takes 60-90 seconds to generate.
Our response times for typical results pages are in the order of 1-2 seconds, and server load is not high.

Testing this after a restart did not improve response times - i.e. it's not a memory exhaustion problem.

(Punitive slowing of results pages for large numbers of failures could be viewed as a feature I guess).