I decided to see what I could get out of my HD5850 overclock, and I thought some of you might find this interesting. I have a lot of data here, and I think this may be of help both to those who are overclocking their HD5850, and to those who are generally interested in scaling with core/memory speed, voltage, and power use.
Test was at 1920x1200/4xAA/16xAF/HBAO, in a single-player game (for consistency).
725/1000 Clock
50.8fps
1.0v core/232 watts (undervolted for the heck of it - doesn't save much)
755/1125 Clock
53.8fps, 6% higher than stock with 4% higher clock and 12.5% higher memory
1.087v core/238 watts (2.5% higher than stock)
850/1200 Clock
59.6fps, 17% higher than stock with 17% higher clock/20% higher memory
1.087v core/267 watts (15% higher than stock)
925/1200 Clock
62.2fps, 22% higher than stock with 28% higher clock/20% higher memory
1.15v core/292 watts (26% higher than stock)
935/1225 Clock*
63.6fps, 25% higher than stock with 29% higher clock/22.5% higher memory
1.15v core/296 watts (28% higher that stock)
*FYI - I ran a 37% fan with my reference cooler and leveled off at 71C at these clocks. I had one crash at this speed, however, so I've backed it down to 925 core.
Because I'm adjusting both core and memory, you can't do a straight core clock analysis, but I think you can assume that if you increase both the core and the memory proportionally, you will get at least 75% scaling with clock increases. That's pretty amazing, I'd say. Sadly, I've run out of memory headroom, even if more voltage would up the core clock (I don't want to go higher actually, for power/temp reasons). The system power draw is almost proportional as well, with spikes as I change voltage. Keep in mind this is for the system as a whole, so in fact the FPS is not scaling directly with VGA power. You definitely pay a penalty in watts as you go for higher FPS. I might post this to the VGA forum, but I thought I'd show people here first, since I did this all to get more out of BC2.
Big shout out to MSI Afterburner, which allowed me to assign my five tested settings to hotkeys - very helpful!