What are your settings for CPU usage now? Or to make it simple, post the entire global_prefs.xml if using web preferences or global_prefs_override.xml if using local preferences (both files in BOINC data directory).

<global_preferences>
   <run_on_batteries>0</run_on_batteries>
   <run_if_user_active>1</run_if_user_active>
   <run_gpu_if_user_active>1</run_gpu_if_user_active>
   <suspend_cpu_usage>60.000000</suspend_cpu_usage>
   <start_hour>0.000000</start_hour>
   <end_hour>0.000000</end_hour>
   <net_start_hour>0.000000</net_start_hour>
   <net_end_hour>0.000000</net_end_hour>
   <leave_apps_in_memory>1</leave_apps_in_memory>
   <confirm_before_connecting>0</confirm_before_connecting>
   <hangup_if_dialed>0</hangup_if_dialed>
   <dont_verify_images>0</dont_verify_images>
   <work_buf_min_days>0.100000</work_buf_min_days>
   <work_buf_additional_days>0.500000</work_buf_additional_days>
   <max_ncpus_pct>0.000000</max_ncpus_pct>
   <cpu_scheduling_period_minutes>60.000000</cpu_scheduling_period_minutes>
   <disk_interval>60.000000</disk_interval>
   <disk_max_used_gb>10.000000</disk_max_used_gb>
   <disk_max_used_pct>50.000000</disk_max_used_pct>
   <disk_min_free_gb>0.100000</disk_min_free_gb>
   <vm_max_used_pct>75.000000</vm_max_used_pct>
   <ram_max_used_busy_pct>50.000000</ram_max_used_busy_pct>
   <ram_max_used_idle_pct>90.000000</ram_max_used_idle_pct>
   <max_bytes_sec_up>0.000000</max_bytes_sec_up>
   <max_bytes_sec_down>0.000000</max_bytes_sec_down>
   <cpu_usage_limit>100.000000</cpu_usage_limit>
   <daily_xfer_limit_mb>0.000000</daily_xfer_limit_mb>
   <daily_xfer_period_days>0</daily_xfer_period_days>
</global_preferences>

Well, if they started together and are still running that isn't very surprising...

the only thing that's strange, is that (according to your task list) you are using 3 hours runtime perference, so the watchdog should kill them after 7 hours... unless they changed here something.

So I assume, that we are talking about this Windows 7 computer and this Windows 8 computer. The results on both this computers look OK so far, so it does not look like a general problem with rosetta.

well, it's possible that those WUs have some very long running models so they won't checkpoint untill they are finished. Are they "running" and using any CPU time? If not, restart BOINC, if they still don't use any CPU time abort them and get some other ones.

Are you rebooting to switch Windows versions when the tasks reset?

If you have some Rosetta tasks running at the same time as other tasks, are you saying that all of the Rosetta tasks issue a message about not finding a 'finish' at the same time?

And are the other non-Rosetta tasks effected?

Have you altered any other settings? How about swap space and memory usage?