Bitcoin Forum

I snagged a used 6870 fairly cheap about a week ago and have had it mining Litecoin, but thought I'd give Terracoin a spin as it's paying more.  However, I keep getting nothing but hardware errors.  I've downgraded the driver from 13.1 to 12.10, I've switched from Terracoin mining on P2Pool to Bitcoin mining on Eclipse, I've wiped out the settings and gone back to defaults.  Right now, my config looks like this, and it's still producing nothing but hardware errors.  The only change is to reduce gpu-threads to 1:


Temperature isn't skyrocketing out of control...in fact, it's lower than the ~80°C I was getting with Litecoin mining. What am I missing here?

(Underlying system is 64-bit Ubuntu Server 12.04 LTS...not my usual Linux flavor, but this box has the biggest power supply I have.  cgminer was built from source pulled from GitHub.)

 First i suggest having 2 different .conf files for your litecoin and bitcoin mining and swap them around when you want to change rather that altering the single file.
I think the main problem is the litecoin parameter's in the config file but "algo" : "sse2_64", definitely needs to go so delete that line.

But mainly i suggest just running cgminer with no config file at all and manually type in the pool info when asked, this will run with all the default bitcoin settings and should work. then when your confident it does work you can go about customising your own config file.

I have two separate files (cgminer.conf.bitcoin and cgminer.conf.litecoin), with cgminer.conf as a symbolic link to whichever one I want active.


I think I'll give that a try once the Jalapeños arrive, when monkeying around with miner configs won't have as much of an effect on my income.

What happens if you just run cgminer with the bare minimum of config?

I saw there was a newer version of cgminer available, so I grabbed a prebuilt binary, uninstalled the older version I had built, zeroed out the config file, and erased the compiled OpenCL binaries.  I still get nothing but hardware errors with Bitcoin mining.  On the other hand, I think I've picked up a few tens of kH/s in Litecoin mining, so there's that.

Hey i was actually about to pick up one of these cards. What type of hash rates were you getting with it while it was working properly?

I'm getting about 300 kH/s from it with Litecoin mining.

I figured out what I was doing wrong: when I set up this box for mining, I had installed the latest AMD APP SDK, which is v2.8.  From the cgminer README:


Derp.

I tried installing 2.5 since I have a 6870, but cgminer (whether using the prebuilt binary or one I built from source) segfaulted a second or two after startup. I think it was a libstdc++ conflict of some sort.  As things stand now, I have v12.10 drivers, v2.6 APP SDK, and v5.0 ADL SDK installed, and cgminer 3.1.0 built from source.  I let it mine against EclipseMC for a few minutes...saw that it was getting a few shares accepted. Since other coins are currently more profitable to mine, I'm not currently mining Bitcoin...but if the bottom falls out of the different altcoins or if an sha256 altcoin becomes more profitable than an scrypt altcoin, I can switch over to that now.

One thing I noticed: the fan runs at a much slower speed when doing sha256 mining.  While keeping the GPU at about the same temperature, the fan was running at about 1600 rpm or so.  Doing scrypt mining, it usually runs at about 3400 rpm.  Temperature is about the same either way: 65-67°C in a cheap midtower case with the lid off (lid on raises the temperature to around 80°C). The fan on the 7750 in my main mining rig behaves similarly: fan runs (IIRC) at about 40% or so when doing sha256 mining, but at 85% when doing scrypt mining.