Terry,
I've seen the same here. Moo! WU's on a Llano/HD 6670 combo normally take around 33 minutes (~2000 seconds), but some can hang out for as long as 3 hours (~10,000 seconds)
What helps is a BOINC version past 7.0.40 (they're now at 7.0.62) and using a app_config.xml file -note that it is not the same as the app_info.xml from before 7.0.40, but has to be placed in the same folder, the project folder-
Code:
<app_config>
<app>
<name>dnetc</name>
<gpu_versions>
<gpu_usage>0.50</gpu_usage>
<cpu_usage>0.15</cpu_usage>
</gpu_versions>
</app>
</app_config>
note the cpu_usage value I use here, triple that of the 'normal' value