How to get 2 x 7950 HDs working with cgminer?? Works fine with 1 card only.

[seocrow]

Hi

Im building my first mining rig. Spec as 2 Sapphire Radeon 7950s Boost 3Gb for GPUs.

Im using Xubuntu and cgminer. Everything was working fine with one card but Im having issues with 2 cards.


Questions for the expert miners

1) Do I need to connect the Bridge Crossfire Cables between the 2 cards. Im still not 100% sure if these are needed for cgminer on Ubuntu
2) What would you suggest I run for a basic config to get these 2 cards mining.

Currently I seem to be able to get GPU 0 mining but GPU 1 appears to fail and cgminer sets the card to OFF. I can stop this by removing the line
export GPU_MAX_ALLOC_PERCENT=100 from my script.. I thought this was needed to crank up the kh/ps.


Both GPU's appear when I run aticonfig list and they also appear if I run cgminer -n

Any idea why GPU 1 is failing like this, is it config or could the GPU be faulty. The temperature for GPU 1 is also a lot lower at 49% where as GPU 1 is running around 80c.

What intensity would you suggest I use for these cards? I ran at 20 and it freezes the screen and eventually the whole board freezes and I need to do a CMOS reset to get up and running again..

Im almost there..Just need to get my 2nd GPU Card working...  

I really don't want to have to install Windows. I really want to try and get this bad boy working on Xubuntu.

[seocrow]

Reading up some people say that there is a loss of kw/ps if you connect a Crosslink Bridge between the 2 GPU's. Is this correct?

Do you recommend installing the Generic ATI Drivers or downloading propitiatory drivers from the ATI website?

[seocrow]

Hoping someone else here has experience of Ubuntu and cgminer with dual cards. Ill be trying some more things later, I may try installing ATI linux drivers direct from ATIs website.

[nybbler905]

1) take this with ' a pound of salt ' as I have no GPU cards capable of mining
2) every thing i've been doing to resurect a 8600GT card ( while using a 7300 ) points me to having to have the cards use the link to get the other to do ANYTHING.
3) all the photos i've seen on multicard rigs ( 2 or 4 rig cards especially and the odd 3 card ) HAVE the cable across the top connecting all of them

i'd start with connecting the cable, reset all settings and see if you ' just get ' a higher hash rate then start messing between the GPUs.

My system is on Winblows so what i got is GUIMiner and i also do CPU mining.  I set tabs for each CPU afinity and a different directory ( copy in to new folder so the path is different for the same program) and would set up similar for GPU mining ( got the tab waiting on the 8600GT to have the life back in it, not likely in a PCIx16 1.0a slot on an intel board ).

Start with the simple ( and working) and build from there.

[tonightwefeast]

Reading up some people say that there is a loss of kw/ps if you connect a Crosslink Bridge between the 2 GPU's. Is this correct?

Do you recommend installing the Generic ATI Drivers or downloading propitiatory drivers from the ATI website?

Hello, I know this was posted a 11 days ago but just to clarify: GPUs do not need to be crosslinked, it does infact lower their hash rate.

TWF

[joulesbeef]

as long as crossfire is turned of, i havent noticed a since hash loss from having them linked.



as for your gpu problems, try bfgminer.. you can use yoru cgminer scripts as it is just a fork.

I'm on windows but I had problems with cgminer and my cards and bfg just worked with zero issues... the way cgminer used to work for me.

[RustyGunz]

Although I am using GUIminer on Windows, I am using 2 7950's so i can give some insight here. I have tried mining with both crossfire on and crossfire off (just a flip of a switch with the control center). I have noticed MAYBE a 5Mh/s difference between the two, which i consider irrelevant. I also use this computer for gaming, so Xfire on is really the better option for me anyway. The cards are both HIS 7950 IceQ2's OC'd to 1150Mhz. I get just under 600Mh/s on each when i'm not running anything else. Your GPU1 will always run hotter, just because of the thermal dynamics of having 2 cards stacked so closely to each other. If you are using MSI afterburner (which I highly recommend), set the user fan progression so that you can keep temps of GPU1 sub 80c -my made up heat threshold. My curve is set so that if card is 70c, fan is 75%- 80c, 85% etc etc. Remember, through Afterburner I've Oc'd both cards from 950 to 1150Mhz so your results could vary noticeably if you opt not to go that route.

[gotobed]

Hi seocrow - did you get a fix for this?

I'm having the exact same problem with same cards

2x sapphire 7950
Ubuntu
cgminer

exact same issues

[djmarsat]

You're better on Windows. The drivers are better. Don't bother with CrossFire for mining. Get a copy of Vista, it's not much these days ($20 - $30)

[djmarsat]

Reading up some people say that there is a loss of kw/ps if you connect a Crosslink Bridge between the 2 GPU's. Is this correct?

From tests I've done, yes.

[gotobed]

You're better on Windows. The drivers are better. Don't bother with CrossFire for mining. Get a copy of Vista, it's not much these days ($20 - $30)

Will probably try windows as a last resort. Would be great to get it going on linux though if its possible.

[seocrow]

Folks. Whatever you do. Do not use Windows. Don't give up on Linux. Windows OS Sucks.

My system is now working and is running on XUbuntu now without any issues. Hash rates are high. I have built 4 more rigs with the same settings with no further problems.

To resolve the issue ensure you install the Linux AMD Drivers.

Follow these instructions here to fix:

https://forum.litecoin.net/index.php/topic,2341.msg15071.html#msg15071


I have also implemented a VNC Server and Apache Server so I can monitor my miners using Web Browsers on other machines and I also recently added automatic email notification so that my Rigs Email me whenever they Start Up or Reboot. Very useful to let you know if there are issues with your Rigs without having to constantly monitor them.

Instructions to add Auto Email Notification are here on my blog

http://litecoinsblog.com/automatic-email-notification-for-mining-rig-startup-or-reboot/

[gotobed]

Big thanks to SEOCROW for helping get my rig sorted.

Was having all sort of problems getting 2x7950s going on Linux.

Seocrow did a remote access session and got the rig running sweet as a nut.

2x Sapphire 7950s hashing away at 600 - 650kh/s each
Also installed a useful email notfication system if rig reboots.

Ubuntu was causing problems so we set it up using Xubuntu and with some other tweaking now all is well.

This was seriously helpful. Thanks!

 

[Tywill]

Using 2 7950s with cgminer, so far no issues with this rig