Ok important stuff 1st:
max OC @stock volts so far w/ cgminer: -I 5 -w 256
950/1010/1.1 volts 110 MHash/s at 90
watts (90-55)=35 watts for 110/35= 3.14 Mhash/w
voltage appears to be locked in the bios to certain speeds. I could not get the voltage to drop until I underclocked the core clock to 400 Mhz.
At 400/1010/.95 volts gave me 50 Mhash using 15 watts for 50/15= 3.33 Mhash/w
I don't think the #'s are going to change appreciably until the gcn kernels get better or the tools to edit the new 7xxx bios appear.
Card is an Asus HD-7750-0-1-GD5
$109 at Newegg
system idle: 55 watts
using the catalyst 12.3
drivers (aka 8.95RC) with phoenix 1.7.5 with diakgcn kernel. aggression=12 vectors2 and worksize=256 (128 lost a few Mhash).
stock 820/1150/1.1 volts 103 Mhash/s at 125 watts (125-55)= 70 watts mining for 103/70= 1.476 Mhash/w
max oc with garbage Asus GPUTweak utility:
870/1010/1.13 volts 109 Mhash/s at 130 watts (130-55) = 75 watts for 109/75= 1.45 Mhash/w
max underclock with crappy Asus util:
770/1010/1.09 volts 97 Mhash/s at 120 watts (120-55)= 65 watts for 97/65= 1.49 Mhash/w
system is a clean install of win7 32 bit. MSI Afterburner is useless for anything except graphs. Trixx is even more useless for this card. Asus utility has a very narrow OC/UC range and the sliders for voltage/gpu clock are annoyingly locked together.
Fan speed never goes over 40% even at max clocks, temp never goes over 65C. If set manually, the fan isnt audible until >60%. System is caseless.
I got cgminer working!! I had to remove the app sdk that 12.3 installed and then go delete amdocl.dll and opencl.dll in win/system32 and then install the 2.6rc3 opencl. This gave me the magic 831 that let cgminer build its bins. Latest diakgcn kernel (diakgcn120216.cl) didn't find any shares tho, it just sat there showing Mhashes, but not actually finding anything. So I am using the default poclbm kernel.
Much better Mhash/w numbers and superior overclocking control.
Gonna let cgminer run at those clocks at the top and go get some sleep. Will tweak some under/overvolting tomorrow. I have no idea why power usage is that drastically different for the 2 programs. I even rebooted the machine and restarted cgminer just to be sure everything was right.