Looks like some numbers were off.
Thanks for the updated data. I updated my stats above.
7770 124% <-stud ?
7950 92% <- dud ?
The results look more in line with what one would expect now. On paper, really no standouts over the 7970 other than the 7770. Even that seems dubious. 6x7770s would be = ~2x 7970s. Sure you save a few dollars but density per server is going to be low.
So IMHO if you want to hash w/ 7000 series your options are:
a) get 7970 seems pretty safe bet at this point
b) wait for 7990.
c) wait to see if any of the smaller cards is an "overclocking champ".
Thanks for the insight D&T.
Your posts are always pure gold
Which card is best in terms of MHash/$ and density ?
Waiting for 7990 or 7890 ...
New specs and pictures: http://www.techspot.com/review/504-amd-radeon-7870-7850/
Also new prices: 7870 349$ list price up from 299$
By my calculations, assuming a 7970 can achieve 700MH/s at a very high overclock, (1280/2048) * 700MH/s = ~437 MHs, assuming the 7870 can OC just as high. Divided by 350$, and at best you get 1.25MHs per $, not including tax, plus board partner fees.
The 7970 was supposed to be 549$, but even today the cheapest one I can find is 582$ new. A 7870 with a decent cooler will probably run you 390-400$ after tax. I had very high hopes for these as well, I figured 299$ for the 7870 sounded too good to be true, but I wasn't expecting the shader count to drop as well
Someone needs to post BTC numbers.
I doubt it getting more than 230 MHash/s though.
Proove me wrong.
It should get much more than that easily.
Mining performance is linearly proportional to clockspeed and shader count among the same architecture, so we can compare it to 7970:
7970 has 2048 shaders, stock clock of 925MHz. It gets about 556MH/s.
7870 has 1280 shaders, stock clock of 1GHz. It should get about (1280/2048)*(1000/925)*556MH/s = 375.7 MH/s. However you can probably clock it to about same numbers as a 7970, so overclocked it could get e.g (1150/1000)*375.7 = 432MH/s. Some can even clock their 7970s to 1.2+ GHz, so 450+ MH/s might be possible if these clock as good.
Not exceptional, but better than 6900 series, with better power consumption. Although against 5870 it doesn't fare as well, probably has about the same power consumption and hashrate, albeit at higher price.
Edit: Revised numbers slightly upwards, 7970 gets 556MH/s not 550
Oops, didn't read far back enough, sorry for the double post