Litecoin build for noobs: 3x 7950s (1.8 MH/s) in a $10 crate case

[AmDD]

I see several people reporting incredible performance efficiencies in this thread and I want to know your secret.  I'm interested in what settings you are running.

Here's what I have:
- ASRock Extreme 4
- Sempron 145
- 4GB RAM
- USB Flash Drive
- PC Power and Cooling Silencer MKIII 1200 (Platinum rated)
- 4x Sapphire 2L 7950s

I flashed my cards to undervolt them to 1.09V (using Sapphire Twin-X bios).  Stock bios was 1.25V unlocked, but needed to flash for Linux.
I run BAMT with CGMiner.
I currently run them at 1050 core/1500 memclock (.7 relation seems best) => ~625kh/s each and my kill-a-watt reads around 950w

Estimating high, lets say everything except the GPUs pulls 100 watts (i.e. CPU/RAM/USB/Mobo), that means each of my cards is pulling roughly 193.5w (@92% PSU efficiency).  Using the same estimation of 100w (CPU/RAM/HDD/Mobo), I see people with setups pulling 155-175w (a generous estimation of 90% PSU efficiency) per card and getting better hash rates on top of that.

If someone is able to help me increase my efficiency to these numbers, I will gladly send some LTC your way for your help!

Do you use powered risers? I have nearly the same setup but with 3 cards.

I cant help with making your system more efficient, sorry.

[bdub]

Do you use powered risers? I have nearly the same setup but with 3 cards.

I cant help with making your system more efficient, sorry.

Yes, I use 2 powered risers, 2 cards run off the board.  You could probably run 3 unpowered and 1 powered, but I had an extra powered laying around so that's what I used.

[Vigil]

Someone needs to slow down the difficulty increase. I have four cards, two of which I haven't even been able to use yet because of how long it takes to get risers - had them for a week. At this point, four cards won't do what two would do when I ordered the first two and I have only been running two cards for a week since the difficulty was 230-290, which was about 3 weeks ago. Its insane.

If you decide to get into mining make sure you have everything you need as soon as you get your cards - if you are going to run 4 cards, buy a MB with 4 PCI-e. Risers will take 2-4 weeks. Make sure rush deliver your cards, it will be worth it. and get them mining as soon as you get them. I have only mined about 20 LTC in 3 weeks when I should have at least 40 or more - I've got 4x7950s. I spent a chunk of change and have missed out on the opportunity to fully utilize what I had. Don't make the same mistake as me.

[msm595]

I completely agree, it's crazy. My cards were delayed two weeks and I lost what is now a month and a half of mining.

[rob1313]

would like to see if i can get help with this. i got a 3x 7950 rig and 2 cards work perfect but the 3rd only get about 80kh/s i got a good 850 watt psu and it pulls 500 watts running like this. 1 card is plugged in to board and the other 2 are on riser whole system is in a crate. 1 card is hooked up via mole connectors. motherboard is sli rated and so is psu. mother board has 5 picE slots i moved cards around and switched power cables. Using cg miner and card show up as 600,80,600 Kh/s.
Has any one run into this and know a common cause.
video cardhttp://www.newegg.com/Product/Product.aspx?Item=N82E16814125414
motherboardhttp://www.newegg.com/Product/Product.aspx?Item=N82E16813128509
PSUhttp://www.newegg.com/Product/Product.aspx?Item=N82E16817139015

Thanks you all for you help with this matter. i seen a few other post similar to this but no replies to them

[fcmatt]

would like to see if i can get help with this. i got a 3x 7950 rig and 2 cards work perfect but the 3rd only get about 80kh/s i got a good 850 watt psu and it pulls 500 watts running like this. 1 card is plugged in to board and the other 2 are on riser whole system is in a crate. 1 card is hooked up via mole connectors. motherboard is sli rated and so is psu. mother board has 5 picE slots i moved cards around and switched power cables. Using cg miner and card show up as 600,80,600 Kh/s.
Has any one run into this and know a common cause.
video cardhttp://www.newegg.com/Product/Product.aspx?Item=N82E16814125414
motherboardhttp://www.newegg.com/Product/Product.aspx?Item=N82E16813128509
PSUhttp://www.newegg.com/Product/Product.aspx?Item=N82E16817139015

Thanks you all for you help with this matter. i seen a few other post similar to this but no replies to them

What software do you have installed? List everything you installed with version pls.

[rob1313]

Currently installed is

cg miner 2.11.4
win8 64 bit
amd control center vision 2013.0320.2223.3847
catalyst 13.3
driver packagin version 12.10.17-130320a-154717e-ati

 teamviewer and then every thing else is stock machine is up to date on win update.

[fcmatt]

Currently installed is

cg miner 2.11.4
win8 64 bit
amd control center vision 2013.0320.2223.3847
catalyst 13.3
driver packagin version 12.10.17-130320a-154717e-ati

 teamviewer and then every thing else is stock machine is up to date on win update.

Cgminer is older but not bad.
Never used win 8. Only 7 64bit.
Amd ccc can be turned off. Try installing msi afterburner with overclock info put in config file. Google that.
13.3 should be ok. But get it from website. Not on install discs from packages you get. Like mb or vid card.

I am hoping msi afterburner sheds some light on things. Nifty program.

[fcmatt]

Oh, and tell us how you are running cgminer pls.

[rob1313]

cgminer i double click it and it runs. if i put the system to btc the low hash rate card gets 250 mh/s while other 2 are at 500 mh/s.

i am uninstalling control center now. i was giving win 8 for free from a friend why i use it.

[fcmatt]

cgminer i double click it and it runs. if i put the system to btc the low hash rate card gets 250 mh/s while other 2 are at 500 mh/s.

Most of us give args to cgminer to tell it how to run. It might be setting intensity very low on one card.
I know i just do not double click it.

[rob1313]

cgminer i double click it and it runs. if i put the system to btc the low hash rate card gets 250 mh/s while other 2 are at 500 mh/s.

Most of us give args to cgminer to tell it how to run. It might be setting intensity very low on one card.
I know i just do not double click it.

after i open it i some time set setting but right now all i have is intensity = 18 in config for all 3 cards i have no other paramater set right now. when i run 2 cards i never had a problem with it like that

[fcmatt]

cgminer i double click it and it runs. if i put the system to btc the low hash rate card gets 250 mh/s while other 2 are at 500 mh/s.

Most of us give args to cgminer to tell it how to run. It might be setting intensity very low on one card.
I know i just do not double click it.

after i open it i some time set setting but right now all i have is intensity = 18 in config for all 3 cards i have no other paramater set right now. when i run 2 cards i never had a problem with it like that

i assume you have tried all 3 cards individually or in pairs and no one card stands out as a problem?

i was hoping this was some type of simple mistake but i am out of guesses...

[rob1313]

i tried all card in all slots a no go. i hooked up a fpga for a bit and now all of a suddon it started workign correctly after 2 hours trying to figure it out .

[fcmatt]

i tried all card in all slots a no go. i hooked up a fpga for a bit and now all of a suddon it started workign correctly after 2 hours trying to figure it out .

so the problem is solved? go figure.

[rob1313]

i tried all card in all slots a no go. i hooked up a fpga for a bit and now all of a suddon it started workign correctly after 2 hours trying to figure it out .

so the problem is solved? go figure.

it seams to be only thing i did was unistall ccc and hook up a fpga and mined with bitminer software then all of a sudden it all worked.

[rob1313]

i tried all card in all slots a no go. i hooked up a fpga for a bit and now all of a suddon it started workign correctly after 2 hours trying to figure it out .

so the problem is solved? go figure.

it seams to be only thing i did was unistall ccc and hook up a fpga and mined with bitminer software then all of a sudden it all worked.

well i spoke too soon i restarted system and it went bank down again. this is so crazy. oh well back to the drawign board.

Edit:
I found the problem, it seams the card runs low when i have a monitor plugged in on start up. if i unplug it and restart it runs perfect. thanks for the help i guees i never thought of NOT to use a monmitor

[neil_mccauley]

Here is my crate rig inspired by this thread:
http://i101.photobucket.com/albums/m79/kalmstyle/81FB9D3B-57F4-4BFC-8CA3-00BC344EA39D-73903-000029AF9862C38F_zps8d13dcc8.jpg

http://i101.photobucket.com/albums/m79/kalmstyle/EF45FE30-90E9-4B05-A0E2-21B384FE5050-73903-000029AF8BFF672E_zps18c2214f.jpg
Only 2 GPUs and one riser right now.  Another 7950 and 2 risers are in the mail and will be here later this week.

PVC pipe is only temporary until I get the risers and the third card, at which point all will be mounted to the crate.

[spoid]

as this is called the thread for the first rig - is there also a known good combination for a second one?
i.e. a combination that runs stable with 4 7950s?
is there a clear "king" of 7950s which definitely runs at the efficiency stated by tacominer (~600 kh/s per card at 625 W from the wall)? I could only get to 750 W with 580 kh/s per card with voltage unlocked sapphire OCs.

Mine came with 1.250 stock voltage, 950 clock speed and 1250 memory.
For scrypt, I could get them down to 1.075 voltage at 1050 clock speed and 1418 memory. I cannot seem to find a better relation between hashrate and electricity usage. I read about people buying card that come with 0.9 stock voltage...

I looked through countless threads but I cannot find a description of a card that is guaranteed to be good. Since "sapphire 7950" is not enough since there will be vapor X and OC and 4L and whatnot, and even given this specification there will probably still be different subtypes.

Also, does anyone have a 7950 where the memory can be undervolted seperately? I tried the modded sapphire trixx version but no luck.

Also, what's up with this guy: http://www.reddit.com/r/litecoin/comments/1cbg51/my_7950s_are_at_800k_somehowprt_scr/

[ofeefee]

on the rig, do you just set fan to "100", or let it run at "auto"?