It looks like ALL games use the same frequency.
The point to all of this is I was afraid of getting a high-end card wasting lots of watts just to check email or play some simple game. THIS DOES NOT SEEM TO BE THE CASE.
Interesting normal games and Terraria both use 850 Mhz - but Terraria doesn't seem to make the card work as hard. I think because some cores are disabled.
If you got these results with a 5770, a 6000 or 7000 series card should do even better.
It looks like 7970 HERE WE COME