Multi-GPU Litecoin mining (AMD 7870 + R9-270X)

December 22nd at 12:00am

Like many people, my interest in cryptocurrency increased about 1000% once Bitcoin got above $800/1BTC. Seeing as the Bitcoin ship has probably sailed (requires ASICs to mine effectively at this point) I looked at the myriad of other currencies that have sprung up recently. I Settled on mining Litecoins as they seem to be minable on GPU and appear to have a better reputation than some of the lesser known coins.

This post will walk through how I got my multi-GPU litecoin mining rig up and running with Ubuntu 12.04.

References

Hardware

Here is what I'm running in my home-made Litecoin mining rig. Most of it came from a holiday bundle that newegg had available a couple weeks back.

Newegg holiday bundle:

  • Enermax Mid-size ATX Tower [newegg link]
  • BIOSTAR TA970 AM3+ AMD 970 [newegg link]
  • G.SKILL Sniper (2 x 4GB) DDR3 1600 (PC3 12800) F3-12800CL9D-8GBSR [newegg link]
  • AMD FX-8350 Vishera 4.0GHz Socket AM3+ 125W Eight-Core (FD8350FRHKBOX) [newegg link]
  • XFX Core Edition FX-787A-CNFC Radeon HD 7870 GHz Edition [newegg link]
  • Rosewill RP600V2-S-SL 600W [newegg link]
  • WD10EZEX 1TB 7200 RPM 64MB Cache SATA 6.0Gb/s 3.5" [newegg link]

 

Additional Graphics Card:

  • Gigabyte R9 270X GDDR5-2GB 2xDVI/HDMI/DP OC Graphics Card (GV-R927XOC-2GD) [amazon link]

 

Home-Made Monitor Dummy plug:

 

I was going to get an R9-280X, but those appear to be sold out for awhile. I was able to get the 270X much sooner, so even though it is slower I would rather have something than nothing.

Positioning the cards in th 2 16x PCI Express slots was a bit tricky. I originally had the 7870 in the slot closest to the CPU. Unfortunately, this didn't seem to let me use the 270X in the other slot. The optimal configuration for me was to have the 270X in the PCI-Express slot closest to the CPU while moving the 7870 to the PCI-Express slot furthest away from the CPU. Even then, spacing is super tight between the cards

 

Hardware temperature notes

When I had everything connected and running in my living room the 270X had a temperature of 95 Degrees celsius and the 7870 was running around 80 Degrees celsius.

Once I moved the rig downstairs, laid it on its side and removed the top case, temperatures improved significantly. The 270X runs between 76 and 78 Degrees while the 7870 runs at a 'cool' 67 Degrees.

Software

I went for a linux base instead of windows to save me the $$ on purchasing the OS license. It did take a lot longer to configure, though, so you may want to consider going down the windows route just for ease of configuration and use.

Configuration

Now for the fun part: Configuring everything to work correctly

Note 1: While technically CGMiner will mine litecoin up to & inclding version 3.7.2, I was only able to reliably run version 3.3.2 without running into the libudev.so.1 dependency problem (which doesn't work on ubuntu 12.04)

Note 2: I had NO success in getting ubuntu version 13.10 running. Maybe you will have better luck than me. :)

 

Here's what I did to get everything setup to work

  • Install Ubuntu v12.04
    • If asked, DO NOT install the proprietary drivers that are included with ubuntu
  • Open the Terminal Application
  • Download and install the AMD Catalyst 13.12 drivers
    • Install your Mointor Dummy Plug in the monitor that does not have a monitor plugged in
    • Reboot your computer

  • Log back in to your desktop
  • Open the Terminal Application
  • Run these commands to setup the AMD/ATI Drivers to work with both installed cards
    • sudo aticonfig --adapter=all --initial
    • sudo aticonfig --lsa
      (This should list all of your installed cards)

  • Run this command to download CGMiner v3.3.2:
    • wget http://ck.kolivas.org/apps/cgminer/3.3/cgminer-3.3.2-x86_64-built.tar.bz2
  • Decompress CGMiner with this command:
    • tar jxvf cgminer-3.3.2-x86_64-built.tar.bz2

  • Run this command to ensure that CGMiner can see all of your graphics cards:
    • ./cgminer -n
      (This should show all of your cards)

CGMiner Litecoin run script

Now that everything is configured correctly, you can put together a script to run CGMiner and harness the power of your GPUs for the purpose of mining litecoins. Here is my script that you can tweak. YMMV.

minecoins.sh:

#!/bin/sh
export DISPLAY=:0
export GPU_USE_SYNC_OBJECTS=1
./cgminer --scrypt -o http://global.wemineltc.com:3335 -u i68040.1 -p x  --gpu-engine 850 --gpu-memclock 1500 -w 256 -I 18

 

After running the script, I alter some settings manually using the cgminer UI (since I'm still tuning and trying new settings):

  • Press G to adjust the GPUs
  • Press C to change CPU settings
  • Press 0 to change my R9-270X settings
  • Change GPU-Engine to 1050Mhz
  • Change GPU-Memory to 1250Mhz
  • Exit back to main CGMiner screen

Speed and Power Consumption of my Rig


With everything configured & running I get:

  • Approximately 350 KH/Second with the XFX 7870
  • Approximately 450 KH/Second with the R9-270X
  • About 400W power consumption for everything (As indicated by my Kill-o-watt power meter)