An intermittent failure occurs on ia32 when the bootimage is opt compiled. The last time it happened was at http://jikesrvm.anu.edu.au/cattrack/results/rvmx86lnx64.anu.edu.au/sanity.217/FullAdaptiveMarkCompact/default/SPECjbb2005/SPECjbb2005/Output.txt The build configurations it occurs in include; production (x10), FullAdaptiveMarkCompact (x3), FullAdaptiveCopyMS (x7) and FullAdaptiveGenCopy (x2) To identify the occasions where this occurs you can run the following query against cattrack database SELECT hosts.name as host_name, build_configurations.name AS build_configuration_name, test_configurations.name AS test_configurations_name, test_runs.name AS test_run_name, test_cases.name as test_case_name, test_runs.revision, test_runs.occurred_at, test_runs.id FROM test_runs RIGHT JOIN hosts ON hosts.id = test_runs.host_id RIGHT JOIN build_configurations ON build_configurations.test_run_id = test_runs.id RIGHT JOIN test_configurations ON test_configurations.build_configuration_id = build_configurations.id RIGHT JOIN groups ON groups.test_configuration_id = test_configurations.id RIGHT JOIN test_cases ON test_cases.group_id = groups.id WHERE test_cases.id IN (SELECT test_case_id FROM test_case_outputs WHERE output LIKE '%invalid argument: NaN%') ORDER BY occurred_at DESC