I've just replaced the GTX 660 OEM from my previous entry with a R9 290. Fiddling around with clockspeeds and voltage today, then I'll tally up the results in the next couple days.
Yikes, I completely forgot I said I'd do that once I got busy with the holidays. Anyway, here it is.
NateDawg | SeaSonic SSP-450RT | i5 3350p @ 3.5GHz + Asus R9 290 | 53w idle | 85.5w | P11826 279W | 42.39 points per watt
Changes since last test:
+200mhz CPU clockspeed, small voltage bump
replaced 660oem with an Asus R9 290.
Other Notes:
-290 is at stock speeds (Asus set it higher than reference - 1000mhz core / 1260mhz memory)
-CPU & GPU are both undervolted.
-290 doesn't like running at 144hz - at that refresh rate the vram doesn't idle and stays at 1260mhz, resulting in roughly 92w total system idle and low-mid 40s temperature. Dropping the refresh rate to anything else shaves about 40 watts off as the vram idles at 150mhz and temperature drops to mid 30s. I'm using 120hz due to this behavior. Not sure if all GCN cards do this, or if it is 290/290x specific.
Old test for comparison
NateDawg | SeaSonic SSP-450RT | i5 3350p @ 3.3GHz + 660 OEM | 48w idle | 74.4w | P6097 141W | 43.24 points per watt | Daily use
Additional GPU undervolting/clocking info:
Had run some 3dmark11 benches at a couple other settings and found the results interesting, maybe someone else will too. I reduced the clock speeds and maintained the core-memory speed ratio of default clocks. A voltage offset of -69 was set in Afterburner for all my tests.
Test 1 - 1000mhz core, 1260mhz memory
P11826 279w | 42.39 points per watt
Test 2 - 900mhz core, 1134mhz memory
P11133 234w | 47.58 points per watt
Test 3 - 800mhz core, 1008mhz memory
P10308 210w | 49.09 points per watt
Some rather noticeable gains in efficiency if you ask me.