8.0.1 release performance on Window

I has been using 8.0.0beta 4 for some performance testing and have great
result.
After migrated to 8.0.1 release, I saw a drop of 10 fold in performance.
A large import and update of 10,000 record use to take 1 hr with beta 4
With 8.0.1 release, it take 10 hours to do the exact same task.
Both install is the default install from PGInstall with no tunning. 
Any help in explaining this change in performance will be greatly
appreciated.
Thanks
Randy


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