Have you tried using Rivatuner? I use it for my card and I'm sure it's ok for 64bit..
In fact it is, here's the main page:
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It does say that it only supports up to Catalyst 8.5 but I know with Nvidia drivers that often if the driver is not supported that it will still 'do it's thing' regardless.
Another cool utility I use if Rivatuners not working for me is 'Powerstrip', you can get it here:
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