Under-rated?

[usagi]

Under-rated?

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[Keninishna]

your fine on 800 watt system with two 6950s overclocked. I ran 3 6950s on a 850 watt power supply. I think ATI has been selling more 6950s on average than the 6970s. I have one 6950 with shaders unlocked gets about 355 mh/s and one with locked shaders gets about 333 mh/s so shaders matter imo. The only other differences between the cards is supposedly the 6970s have slightly better memory (not relevant to mining) they have a 6+8 pin power inputs and can draw more power from the PSU, which despite the extra power draw I can't find much difference in performance. The 6970s arguably have better cores for overclocking and can hit 1 ghz easier probably than a 6950 can. However I think if you can get your hands on an unlockable 6950 the price difference isnt worth it for a 6970 imo.

[CyberPhunk]

Depending on the 6950 you get, with overclocking the gpu and underclocking the memory you can get 400Mh/s.

My XFX 6950 with stock bios/unlocked shaders is currently running at 910/625 at 1.175V and I get ~401Mh/s

So, yeah, the 6950's are nice cards.  

[faille]

my i5 2500k with 4x 6950 1gb pulls 820watts from the wall, using a 1200watt psu.

so guessing a good quality 750watt should be fine for you.

[crazybernie]

The "minimum requirements" for a 6950 is a 500Watt power supply... they pull about 169 Watts @ load with stock settings.  I'm running an XFX 6950 @ stock and netting 318Mh/s with a Corsair 600 Watt PS with zero problems.  I wouldn't be scared to add a second card if it had the extra PCI-E connectors.

I question that 8% variance though... the 6970 has more shaders and a higher clock speed... you might be comparing the 6950's with unlocked shaders.  Those cards are getting a little harder to find.... my XFX has a locked bios and I may not be able to unlock those extra shaders (people have been having a 50/50 chance on this particular board revision).

If you do have unlockable 6950's though, you basically already have 6970's.

[onis_uk]

too right they are under rated ! im getting about 400 mh/s each out of my two ! well good !
my 600 watt ocz power supply cut out when i added the second card, so i bought another 850watt one and all
is good 

[Auspician]

I'm running two overclocked 6950's on a 5 year old 750 watt PC Power and Cooling PSU.  You might be able to go even less wattage, considering that in addition to the cards I'm running an overclocked i7, six hard drives, two optical drives, a sound card, a USB PCI card, and seven case fans.

That said, I wouldn't recommend going less than 600 watts for two 6950's in an otherwise bare-bones system.  1000 watts should be more than enough for three 6950's.

[cicada]

I'm running a couple rigs with 2x 1GB XFX 6950s - shaders aren't unlockable on any of them unfortunately, but at 885/760 gpu/mem clocks I get 345mhash/s each.  Sempron single-core 45W CPU and cheap g-skill ram.

Each rig pulls ~410W at the wall.  1000W is lmao.  I got a nice 750W 80+ Corsair PSU expecting more draw, but even adding a third card I won't hit that limit.

[epdp14]

What do you guys think about a 450 or 500 run of the mill power supply for a single 6950? I just bought an ASUS EAH6950 from amazon and didn't think about needing more power for just one card.

[Oldminer]

What do you guys think about a 450 or 500 run of the mill power supply for a single 6950? I just bought an ASUS EAH6950 from amazon and didn't think about needing more power for just one card.

For 1 x 6950 it will be fine. I run 2 x 6950's on a 700W.

[cvicisso]

For your reference: I run 3 x 6950s (adding a 5850 soon) on a 1250 PSU (80+ Gold) and they only draw ~630-640 W.  The cards are non-reference, so I can't unlock the shaders  but with CCC overclocking, I can hit 1 GH/s intermittently (which jives with previous posts). 

[dinzy]

What do you guys think about a 450 or 500 run of the mill power supply for a single 6950? I just bought an ASUS EAH6950 from amazon and didn't think about needing more power for just one card.

For 1 x 6950 it will be fine. I run 2 x 6950's on a 700W.

I have run 1 6950 on a very old, but nice,  450 W PSU and am currently running 2 on a 600 W PSU

[mikeo]

I snagged a nice "open box" MSI R6950-2PM2D2GD5 Radeon HD 6950, which is a reference card, on newegg today. I expect I'll flash it to a 6970 and add it to my miner. That will then be a GPU line-up of 6950 (flashed), 5850, and a 5830. All runing on a OCZ EliteXStream OCZ800EXS-B 800W PSU. Should be fine. If not I'll swap out the Tagan 900W PSU from my gaming maching which requires nowhere near that much PSU.

[bigbeerjr]

I snagged a nice "open box" MSI R6950-2PM2D2GD5 Radeon HD 6950, which is a reference card, on newegg today. I expect I'll flash it to a 6970 and add it to my miner. That will then be a GPU line-up of 6950 (flashed), 6850, and a 5830. All runing on a OCZ EliteXStream OCZ800EXS-B 800W PSU. Should be fine. If not I'll swap out the Tagan 900W PSU from my gaming maching which requires nowhere near that much PSU.

I've got 7 of those cards. You should just unlock the shaders and not flash the 6970 bios. You should see around 360MH/s once you unlock the shaders. Good luck with overclock, I am unable to increase the core voltage since I run linux and just upping the core speed didn't change my hash rate.

--
BigBeerJR

[Imagex]

I have 15 xfx 6950's was lucky on 5 of them to be version 2 and unlocked them, I tryed 11.6 drivers with no luck, what drivers do you think are best?

[fcmatt]

MSI R6950-2PM2D2GD5 's can do 430 mh/s easy.
voltage 1200
core clock 970
mem clock 800
fan at 75
shaders unlocked.
good air movement around the cards. conditioned air that is.
using pocblm whatever with phatk kernel.. making sure it has all the lastest code tweaks.

and that is not pushing it to the max. i used to run 980 core clock but decided to take it a bit easier on the cards
and get excellent stability at a temp of ~54

the 6950 reference cards at a price of 250 are an excellent deal for mining and gaming.
but with the difficulty going up it will be hard to pay them off now days at a fast rate.
they had a rebate too just a while back.. but be careful you are limited to one rebate per household.

oh.. and be careful buying refurb cards. i bought a 5970 refurb and as soon as i pushed it
the 2nd core on it started giving me problems. it was obviously still bad in some way and i returned
it for a refund.. thank goodness. buying new or seeing it in action before you buy is probably the way
to go unless you can return it no questions asked.

[bigbeerjr]

MSI R6950-2PM2D2GD5 's can do 430 mh/s easy.
voltage 1200
core clock 970
mem clock 800
fan at 75
shaders unlocked.
good air movement around the cards. conditioned air that is.
using pocblm whatever with phatk kernel.. making sure it has all the lastest code tweaks.

and that is not pushing it to the max. i used to run 980 core clock but decided to take it a bit easier on the cards
and get excellent stability at a temp of ~54

the 6950 reference cards at a price of 250 are an excellent deal for mining and gaming.
but with the difficulty going up it will be hard to pay them off now days at a fast rate.
they had a rebate too just a while back.. but be careful you are limited to one rebate per household.

oh.. and be careful buying refurb cards. i bought a 5970 refurb and as soon as i pushed it
the 2nd core on it started giving me problems. it was obviously still bad in some way and i returned
it for a refund.. thank goodness. buying new or seeing it in action before you buy is probably the way
to go unless you can return it no questions asked.

How are you changing the voltage?

[jjiimm_64]

I like my 6950's, but I cannot over clock them past 900, even at that the machine will lock up after a while, so I run them at 875 core, mem 310.

I tried to flash them to a 6970, but apparently that hard wired the locked out shaders.  there is some instructions on the internet on how to open the card and connect 2 pins of one of the icchips, but I am reluctant to do that.  I get about 345 Mhash with them with a solid share acceptance rate.

they run a little hot, but that might be because I am also using them as bug zappers here in the shed

[mikeo]

I snagged a nice "open box" MSI R6950-2PM2D2GD5 Radeon HD 6950, which is a reference card, on newegg today. I expect I'll flash it to a 6970 and add it to my miner. That will then be a GPU line-up of 6950 (flashed), 6850, and a 5830. All runing on a OCZ EliteXStream OCZ800EXS-B 800W PSU. Should be fine. If not I'll swap out the Tagan 900W PSU from my gaming maching which requires nowhere near that much PSU.

I've got 7 of those cards. You should just unlock the shaders and not flash the 6970 bios. You should see around 360MH/s once you unlock the shaders. Good luck with overclock, I am unable to increase the core voltage since I run linux and just upping the core speed didn't change my hash rate.

--
BigBeerJR

I though unlocking the shaders required flashing to a 6970 BIOS? I'd be very interested to hear your method.

[bigbeerjr]

I snagged a nice "open box" MSI R6950-2PM2D2GD5 Radeon HD 6950, which is a reference card, on newegg today. I expect I'll flash it to a 6970 and add it to my miner. That will then be a GPU line-up of 6950 (flashed), 6850, and a 5830. All runing on a OCZ EliteXStream OCZ800EXS-B 800W PSU. Should be fine. If not I'll swap out the Tagan 900W PSU from my gaming maching which requires nowhere near that much PSU.

I've got 7 of those cards. You should just unlock the shaders and not flash the 6970 bios. You should see around 360MH/s once you unlock the shaders. Good luck with overclock, I am unable to increase the core voltage since I run linux and just upping the core speed didn't change my hash rate.

--
BigBeerJR

I though unlocking the shaders required flashing to a 6970 BIOS? I'd be very interested to hear your method.

If you download RBE you can simply dump the stock bios via atiflash, open it in RBE and then only unlock the shaders. Afterwards you can flash the modified bios back to the card. On some of the OC boards people don't recommend the 6970 bios because it changes too many timings/etc.