Bitcoin Forum

Hi All,

     I've had a dedicated mining rig with 1x Sapphire 7950 (the version with the single loud fan) mining along at close to 500 hash for three weeks now.  I just recently scored a deal on a Gigabyte HD7950 card, and installed it in this same mining rig.  For some reason, no matter which options I try I am getting a total of max 570 hash.  As of this moment BFG miner is reporting 311 hash from the Sapphire and 265 hash from the Gigabyte.  Anybody know of things I could try / do to get better performance from these two cards?  Below are the current arguments I am using with BFGminer. 

bfgminer -o http://deepbit.net:8332 -u <username> -p <password> -I 7,7 --gpu-powertune 20,20 --gpu-engine 1075,1075 --gpu-memclock 1650,1650 --auto-fan --temp-target 80,80 --temp-overheat 87,87 --temp-cutoff 91,91 -g 1 -w 256,256

I tried lowering the worksize to 64, increasing the threads to 3 and adding a vector of 1 argument, but that did not make a difference.  It looked like it was starting to mine at a high has rate, but evened out as time progressed. 

I did try some searching around the forums before I made my own post, but I am still at a loss. 

What ever ideas or assistance would be grateful. 

Thanks,

Rock

Increase intensity one by one until you get errors or reach the maximum. One thread per GPU is enough.

I get good results with 1 vector, worksize 256 and thread concurrency 14336 on my two 7950s.

Intensity 7 is pretty low. I've noticed on AMD platforms you can go all the way to 20 but on Intel platforms I start getting errors at like 13 so I was usually at 12.

Try upping the intensity?

Hi All,

     Thanks for the responses.  14 Is the highest BFGminer will go.  I tried changing it to 15 or 16 and it still ends up reading 14..  I'm getting about the same hashrate.  At this moment the Sapphire card is hashing away at 285 while the Gigabyte is doing 278.  Really not too sure what I am doing wrong.  Thinking of installing cgminer, and seeing if it is the mining program.  This was working well with the one Sapphire card with an intensity of 7 prior to installing the Gigabyte...   

Thanks for the responses. 

Rock

thread-concurrency is only for scrypt mining right? 

I'm bitcoin mining currently.  Just compiled and installed cgminer.  no love...   i'm wondering if it is a BIOS setting or something...   I tried different pools, different miner programs, changed a bunch of settings.  not really seeing a difference.  Either card works well on it's own.  Getting about 450 - 500 hash from one card mining by itself, which is good for a 7950.  Once I activate the other card the hash rate drops...   Wish I knew what I was doing wrong. 

Rock

install the unlocked voltage bios (search the forums), you're pushing the giga too hard. i run at gpu 1075 mem 1100-1125 for 640khs i20 g1 powertune 7 @ 1.056v tc 25984 and i have 10 cards that will pull between 620-640 khs. some hit 660, and the losers gotta turn down to 1025/1075 @ 620khs.

Yes. I was assuming scrypt because of the high memory clocks. For SHA256, 1650 MHz is a waste of energy. Set memory clocks to 300 MHz or the lowest setting your drivers permit.


By "on its own", do you mean that you have only one card installed in the rig or that one is installed but inactive? Cards not connected to monitors can go into low performance mode in multi-card setups. Download GPU-Z and verify that the current core clocks of your cards are actually 1075 MHz.

Maybe your intensity is too high. With CGMiner, intensity 13 (20 is the highest setting) gives me the best performance. Start with 9 and increase one by one.


Well, it's moderate. 1075 MHz should give you about 560 Mhash/s, and you should be able to overclock the cards a little more.

In CGMIner, try diablo kernel, 1 thread per GPU, 1 vector and worksize 256.

If that fails, which Catalyst version are you using? Have you tried more than one? How are your temps?

Redwitz and suprabitz,

     Thank you so much for your responses!!  I'm going to try your suggestions when I get home from work tonight.  When I was running one card at a time, both were still installed in the machine.  I just disabled one in cgminer.  I tried that in cgminer as well as bfgminer with the same results.  I was getting about 450 - 500 hash from one card mining by itself.  When you enable the second card the first one drops to about 280, and the new one will only hash at about 280 hash as well. 

I'll try the diablo kernel when I get home.  My temps are good.  80 degrees C at the highest for the sapphire card.  The Catalyst version is the latest, i'll get the exact version number tonight.  I was excited to see some traction on the forum posting. 

Thanks Again all!! 

Rock

And I thought my Sapphire 7870 was hashing low at 260-280 at intensity 18. Its a lot weaker than the Cfx 5870 I can push to 395.  The only advantage is its much cooler temps.

Intensities for BTC mining rarely benefit above 9. Intensities above 11 are a mistake on BTC leading to huge lag and slow return of results. Intensities above 14 on BTC lead to garbage being generated and are reserved for scrypt mining. If you are getting the hashrate from two devices that you are expecting from one device, then you are having the issue as described in the cgminer GPU-README below:

Q: I'm getting much lower hashrates than I should be for my GPU?

and

Q: I have multiple GPUs and although many devices show up, it appears to be
working only on one GPU splitting it up.

and

Q: I have some random GPU performance related problem not addressed above.


Documentation is there for a reason, please read it as I spent a lot of time making it.

Does that result in any inconvenience beside the hashrate? I've tried all values from 7 to 15, and 13 gives me the highest hashrate for all my GPUs (3 7950s and a 6870). This is with Diablo kernel and Catalyst 13.1.

I couldn't get my cards to perform as well with the 13.1 driver when I tried it. The latest driver does a stable 620 MH/s at 1200 Core / 800 Memory.

Thanks All! 

I think I kind of have it figured out.  Getting great performance on the Sapphire card, but not that great performance on the Gigabyte one.  I think my problem is windflow with the Gigabyte card.  It keeps overheating.  I'm happy with the performance i'm getting now given the situation. 

Thanks for all the help everybody!! 

Rock