which one is best?

[tminer]

                               PLEASE TELL WHICH ONE OF THE FOLLOWING WILL YIELD THE BEST RESULT


                               (a)   IF USED AS SINGLE AND

                               (b)  IF USED AS CROSSFIRE MODE [X2]


1. Gigabyte AMD Radeon HD 7970 OC 3GB GDDR5 DVI-I/HDMI/2x Mini-Displayport PCI-E 3.0 Graphics Card GV-R797OC-3GD

                                 

                                     OR     


2. PowerColor Radeon HD7970 925 MHz 3GB DDR5 PCI-Express 3.0 x16 Graphics Cards AX7970 3GBD5-M2DHG
                                   
                                   
                                       

                                        OR


3. Sapphire Radeon HD 7970 OC with Boost 3GB DDR5 DL-DVI-I/SL-DVI-D/HD... PCI-Express Graphics Card 11197-03-40G

                                     

[raad287]

i really don't think it's going to matter as long as it's a 7970.

They do get hot though, I would suggest getting the one with the best fan, they tend to scale in price based on that.

[RaTTuS]

you dont need X-fire [in fact you dont want to use it]

[Nolo]

you dont need X-fire [in fact you dont want to use it]

I'd agree that you don't need it.  I get no difference in hash rate using it or not using it.  But I'm using Windows 8 x64.  I've heard that it really doesn't matter for Windows users whether you use crossfire or not, but with Linux you definitely want it disabled. 

[links-pyramining]

None of them. I don't think mining with GPU will be profitable after ASICs will be ready (next months)...

[Gabi]

None of them. I don't think mining with GPU will be profitable after ASICs will be ready (next months)...

^This

[Graet]

I have 5 of
Gigabyte AMD Radeon HD 7970 OC 3GB GDDR5 DVI-I/HDMI/2x Mini-Displayport PCI-E 3.0 Graphics Card GV-R797OC-3GD
690-700Mhash per card
they have been a good card and I will be crossfiring 2 in my desktop when their mining days are over
one of the reasons I choose the 3 fans gigabyte is the volume - I treasure my hearing as I age one reference card drowns these babies out 

buying gfx cards now is a bit late to mine
upgrading your gfx card for some other purpose and mining on it for a few weeks is different

although if you are looking to save some $$ there will be a flood of various 2nd hand GFX cards in a few weeks - just in time for xmas i think

it depends on your reason for the upgrade

[SparroHawc]

None of them. I don't think mining with GPU will be profitable after ASICs will be ready (next months)...

It will continue to be profitable if you don't have to pay for the juice.

[Coiner2600]

I have 5 of
Gigabyte AMD Radeon HD 7970 OC 3GB GDDR5 DVI-I/HDMI/2x Mini-Displayport PCI-E 3.0 Graphics Card GV-R797OC-3GD
690-700Mhash per card

I just bought one of these to start mining (yes, bad time, I know) how do you get your hash rate up there?  I'm at about 600Mhash (give or take) doing nothing outside of the defaults with GUIMiner.

I'm a little nervous about changing the overclocking settings because I don't want to fry my board, but if someone can give me any specific guidance it would be helpful.

OT: If I don't make all my money back on this card mining, it's okay, I might switch to litecoin mining after ASIC's start shipping if the return looks good, or maybe even do folding@home instead...

Edited later on tonite: I tried to launch the AMD/ATI Catalyst utility (win8 64 bit) to poke around and it wouldn't launch.  Un-installed it, deleted the folders, reinstalled it, reinstalled the version from the AMD website for win8, (as opposed to the version provided by Gigabyte for Win 7 and Vista) and so on, nothing works.  This has been documented a variety of places with a variety of solutions, I tried a bunch of stuff, but if that's the way I have to do it I may have to re-install Windows 8.  Not that big a deal since I don't do anything else on the PC, but *this* is why I don't use Windows anymore for personal use...

[notaek]

I have 5 of
Gigabyte AMD Radeon HD 7970 OC 3GB GDDR5 DVI-I/HDMI/2x Mini-Displayport PCI-E 3.0 Graphics Card GV-R797OC-3GD
690-700Mhash per card

I just bought one of these to start mining (yes, bad time, I know) how do you get your hash rate up there?  I'm at about 600Mhash (give or take) doing nothing outside of the defaults with GUIMiner.

I'm a little nervous about changing the overclocking settings because I don't want to fry my board, but if someone can give me any specific guidance it would be helpful.

OT: If I don't make all my money back on this card mining, it's okay, I might switch to litecoin mining after ASIC's start shipping if the return looks good, or maybe even do folding@home instead...

Edited later on tonite: I tried to launch the AMD/ATI Catalyst utility (win8 64 bit) to poke around and it wouldn't launch.  Un-installed it, deleted the folders, reinstalled it, reinstalled the version from the AMD website for win8, (as opposed to the version provided by Gigabyte for Win 7 and Vista) and so on, nothing works.  This has been documented a variety of places with a variety of solutions, I tried a bunch of stuff, but if that's the way I have to do it I may have to re-install Windows 8.  Not that big a deal since I don't do anything else on the PC, but *this* is why I don't use Windows anymore for personal use...

I own the card that you bought.  Nobody really uses Catalyst to overclock... I would use MSI Afterburner. Bump your core clocks up by about 10-20MHz, then mine for a few hours.  If your computer doesn't crash, you can up the clocks by another 10-20MHz again.  When it finally does crash, bring your core clock back to the previous setting it was stable at.  On that card, you can't adjust the voltage so you won't be able to get any crazy overclocks.  This is okay though, because you tend to use a lot more power when you overvolt.  Also, don't worry about cooling for this card.  You will be able to monitor your temperatures in afterburner.  If you have your fans on the auto setting, your card should stay at around 63 degrees C.

Another thing you should do is take the memory clock down to 900MHz.  This is the lowest you can go.  The reason why you do this is to save electricity.  You don't use the memory of the card when you're mining.  Just remember to up it back to what it was originally before you play a game or something.

[mjc]

None of them. I don't think mining with GPU will be profitable after ASICs will be ready (next months)...

+1   Look at Butterfly Labs

[Graet]

I have 5 of
Gigabyte AMD Radeon HD 7970 OC 3GB GDDR5 DVI-I/HDMI/2x Mini-Displayport PCI-E 3.0 Graphics Card GV-R797OC-3GD
690-700Mhash per card

I just bought one of these to start mining (yes, bad time, I know) how do you get your hash rate up there?  I'm at about 600Mhash (give or take) doing nothing outside of the defaults with GUIMiner.

I'm a little nervous about changing the overclocking settings because I don't want to fry my board, but if someone can give me any specific guidance it would be helpful.

OT: If I don't make all my money back on this card mining, it's okay, I might switch to litecoin mining after ASIC's start shipping if the return looks good, or maybe even do folding@home instead...

Edited later on tonite: I tried to launch the AMD/ATI Catalyst utility (win8 64 bit) to poke around and it wouldn't launch.  Un-installed it, deleted the folders, reinstalled it, reinstalled the version from the AMD website for win8, (as opposed to the version provided by Gigabyte for Win 7 and Vista) and so on, nothing works.  This has been documented a variety of places with a variety of solutions, I tried a bunch of stuff, but if that's the way I have to do it I may have to re-install Windows 8.  Not that big a deal since I don't do anything else on the PC, but *this* is why I don't use Windows anymore for personal use...

cgminer with a .bat file containing

cgminer.exe -o au.ozco.in:3333 -u graet.g5 -p 1234 -I 7 -k poclbm --auto-fan --gpu-engine 1060-1160 --auto-gpu --gpu-vddc 0.88 --gpu-memdiff -150 --temp-target 80 --temp-overheat 95

does all my clocking and temperature management

oh and you do need real ATI drivers not gigabytes one, cant help with win8, don't see a point to upgrading yet

[greyhawk]

None of them. I don't think mining with GPU will be profitable after ASICs will be ready (next months)...

+1   Look at Butterfly Labs

The only ones who don't have a chip yet? What about them?

[Coiner2600]

Thanks for the tips from both of you... I'll try it out this weekend.  Wasn't aware MSI Afterburner worked on any mfr's card, though.  It's good I won't need to reinstall Windows 8.