Undervolting a 5870 at 0.95v

[jamesg]

Hello fellow bitcoiners,

I have seen and used undervolt settings at both 1.0v and 0.9v for my 5970s. I have not however been able to find anyone who is running with the voltage at 0.95v.

Anyone doing this?

Thanks,
gigavps

P.S. You can see all of my undervolt settings here -> http://farm.gigamining.com/mgpumon/

[mitak64]

My 5870s run at 810core/275mem @1.00V fine.
Tonight I'll try 0.95 as well.

[Gomeler]

I have only been running my 5870/5850 that support undervolting at 1.0v at 850/200.

Your BFL Single rig is equal to my GPU farm 

[JWU42]

I have yet to devolt the 5870s.  They are able to stay cool enough without the fans running beyond 50%.

My go to for 5970's has been 755/180 @ .99v and curious to hear others comments on a slight OC with lower than 1.162V on their 5870s.

[rograz]

got 2 xfx ref cards running 0.95V at 710/730MHz pulling around 75-80W per card from the wall (80+ bronze psu) I just wish all my non ref cards would do 0.95V as well, :/

[Mousepotato]

What kind of MH/s are you guys getting at these underclock/undervolt settings?

[rograz]

The average for me running 0.95V is around 310 MH/s for my 5870s and around 290 MH/s for my 5850s. Each card was tested individually and they range from 680 Mhz to 740 Mhz for what they can handle with most of them just around 700ish.

[jamesg]

The average for me running 0.95V is around 310 MH/s for my 5870s and around 290 MH/s for my 5850s. Each card was tested individually and they range from 680 Mhz to 740 Mhz for what they can handle with most of them just around 700ish.

Good info. Thanks for posting.

[italeffect]

I have 2 under-volted 5870's.

One at 840/155 and 1v = 384 mh/s
The other at 755/155 and .95v = 347 mh/s

If I try to set the first card to .95v I have to set the engine clock too low to around 400, otherwise it crashes.
The 2nd card is happy as can be at .95v

[jamesg]

I have 2 under-volted 5870's.

One at 840/155 and 1v = 384 mh/s
The other at 755/155 and .95v = 347 mh/s

If I try to set the first card to .95v I have to set the engine clock too low to around 40o, otherwise it crashes.
The 2nd card is happy as can be at .95v

I like the 750/150 at the .95v! 

I'll have to try that out in a little while.

[jamesg]

Your BFL Single rig is equal to my GPU farm 

Those are my hash monsters! 

Best thing about them is that they never crash. They just keep on hashing.

[Mousepotato]

I like the 750/150 at the .95v!  

I'll have to try that out in a little while.

Yeah that sounds like a pretty good cruising speed.  I wonder if these can be volted down any further?  On 5970s you can go down to .90v (610/200) for 550 MH/s, and possibly even lower on the voltage (in the .86-.88v range).  Has anybody had any luck with sub-.95v on 5870s?

[jamesg]

Yeah that sounds like a pretty good cruising speed.  I wonder if these can be volted down any further?  On 5970s you can go down to .90v (610/200) for 550 MH/s, and possibly even lower on the voltage (in the .86-.88v range).  Has anybody had any luck with sub-.95v on 5870s?

I run my 5870s at 650/150/.899v currently for around 295Mh/s.

I tried the 750/150/.95v on a 5x5870 rig and things crashed before they even got started.

[ARapalo]

How much electricity are you really saving with this undervolting?

[zvs]

i suspect there's a point where the diminishing returns become potential profit lost w/ huge undervolting.

right now i have a 5870 running at 1000/300, 1.05v, getting around 460mhash/s

two others are at 980/215, ~1.14v (I forget exactly), getting around 440mhash/s.  In about 5 or 6 hrs here, I'll drop them to 850/215 @ 1.02v... the other one, I just leave at 1000/300 as it never goes above 65oC anyway

(ed: oh, my elec is only 8c per kwh.. i wouldn't undervolt at all except for the heat issue during the day.  still working on an outdoor workshop area to put them in)

[chiropteran]

I've done similar with 5830's

One pair is seemingly stable at C=765  M=200 V=950, putting out 235mhash each

The other pair is is only stable up to C=750 at V=950, for 220mhash per card.

I actually running them at C=870 M=300 V=1050 for now, which is 262mhash per card.

Don't have my watt-meter here today so I can't really say which voltage is more efficient overall.

[Zubilica]

Yeah that sounds like a pretty good cruising speed.  I wonder if these can be volted down any further?  On 5970s you can go down to .90v (610/200) for 550 MH/s, and possibly even lower on the voltage (in the .86-.88v range).  Has anybody had any luck with sub-.95v on 5870s?

I run my 5870s at 650/150/.899v currently for around 295Mh/s.

I tried the 750/150/.95v on a 5x5870 rig and things crashed before they even got started.

Try 775/290/0.96v

[jjshabadoo]

On another note, I get 900 engine, 300 mem at 1.125 but I know plenty of people have posted those numbers. I get about 410-420 mhash, but I use an old version of cgminer because those rigs are linuxcoin and I'm afraid to F with them..lol.

I'll need to under volt soon, so I'll post what I get after this weekend.

[jamesg]

Ok miners. I have been doing some testing of my own and I think I have found some more optimal settings.

Before I was running:

650/150/.899v @ 291Mh/s each and 1455Mh/s total

I am now running two 5x5870 rigs at:

800/150/.959v @ 367Mh/s each and 1835Mh/s total

Looks like the .959v setting is the closest to the .95v I was after and am still able to get the 800 core clock. I am also getting 380Mh/s more out of each rig with these settings which is pretty sweet considering the low voltage.

Try it out and let me know if it works for you.

[Cablez]

Hey gigavps,   what kind of savings do you get from the rig going from same clocks at stock to the new .95V?  Is there a substantial wattage savings?

I am thinking of starting to undervolt my rigs as electricity is killer but stability is real concern.