Could you do us all a favor and post your 3dmark11 score and or vantage score on normal performance setting.
It is quite normal and expected that anyone running at stock settings will get a "your system is performing below others with a similar system". This is because most their database is based on overclocked systems.
You also did not mention brand on that 625w PSU. That is below the recommended power, and unless it's a good brand, it unlikely enough.
It would also be helpful if you downloaded GPU-Z and posted some screenshots for both cards. I'm most interested in what the bus interface says.