Bitcoin Forum

I really wanted to post this in the mining area but it pertains mainly to scrypt and altcoins.

I've got a really strange one that I am unable to figure out.  One of my GPU's is a Sapphire HD7850 1 GB purchased new about two months ago.  The card works fine in benchmark testing and will hash SHA-256 with zero problems.  My issue?  The card flat out will not hash scrypt.

I have been mining for a while and am moderately experienced and comfortable building and rebuilding rigs.  I have other 7850's that I use, along with 7950's and 6850's so I know how to configure miner software, overclock, etc.  I have had this card in various slots in 3 different motherboards and I get the same results.  Either CGMiner crashes, or I get a hash rate of 3 to 4 KH/s.  All machines had ample memory and were running other cards with no issues.

I am out of options with this card and not sure what else to do.  I really can't RMA it as it will run games just fine.  I can mine a bitcoin or two with it but it's really not profitable to use it for that.

Anybody had any experience with this?

I have a Sapphire 7850 that refuses to hash scrypt online (mincoinpool), but works fine for solo mining on my own network. Seriously, its odd.

start by showing us how you run cgminer on the card. paste the full command line args please.
i am thinking the args are somehow not kosher for this card. it sounds like you only have one of this model/brand?
when running cgminer can you show us the cgminer output? does it outright fail to run with an error? does it run and
have output?

Thanks for the response.  I appreciate you taking the time to ask questions.

I have 2 Sapphire 7850's.  This one is 1GB and won't mine scrypt.  The other is 2GB and does it quite well.  Overclocks well also. 

Running GUIMiner overlay, CGMiner engine.

Overclock, under clock, default clocks, does not matter.

Thread concurrency: 12404, but have tried various values as suggested all over the internet. 8192 all the way up to 12,404.
Worksize: 256
Vectors: 1
Intensity: all values from 10 to 19.
GPU threads: 1

All other settings are default GUIMiner settings.

On two different motherboards I got the card to clock 3 to 4 kh/s.  No strange messages.  It keeps mining along, but never goes higher than this.

On the other motherboard it crashed CGMiner and gave a windows program error message.  Here is the output I get from CGMiner:

2013-06-22 22:11:42: Listener for "DGCErundook7850.2" started
2013-06-22 22:11:46: Listener for "DGCErundook7850.2": [2013-06-22 22:11:42] Started cgminer 2.11.3
2013-06-22 22:11:46: Listener for "DGCErundook7850.2": [2013-06-22 22:11:42] Probing for an alive pool
2013-06-22 22:11:46: Listener for "DGCErundook7850.2": [2013-06-22 22:11:44] Maximum buffer memory device 0 supports says 803209216
2013-06-22 22:11:46: Listener for "DGCErundook7850.2": [2013-06-22 22:11:44] Your scrypt settings come to 812908544
2013-06-22 22:11:46: Listener for "DGCErundook7850.2": [2013-06-22 22:11:44] Error -61: clCreateBuffer (padbuffer8), decrease CT or increase LG
2013-06-22 22:11:46: Listener for "DGCErundook7850.2": [2013-06-22 22:11:44] Failed to init GPU thread 0, disabling device 0
2013-06-22 22:11:46: Listener for "DGCErundook7850.2": [2013-06-22 22:11:44] Restarting the GPU from the menu will not fix this.
2013-06-22 22:11:46: Listener for "DGCErundook7850.2": [2013-06-22 22:11:44] Try restarting cgminer.
2013-06-22 22:11:46: Listener for "DGCErundook7850.2": [2013-06-22 22:11:44] Maximum buffer memory device 1 supports says 804257792
2013-06-22 22:11:46: Listener for "DGCErundook7850.2": [2013-06-22 22:11:44] Your scrypt settings come to 812908544
2013-06-22 22:11:46: Listener for "DGCErundook7850.2": [2013-06-22 22:11:44] Error -61: clCreateBuffer (padbuffer8), decrease CT or increase LG
2013-06-22 22:11:46: Listener for "DGCErundook7850.2": [2013-06-22 22:11:44] Failed to init GPU thread 1, disabling device 1
2013-06-22 22:11:46: Listener for "DGCErundook7850.2": (1s):0.000 (avg):0.000h/s | Q:1  A:0  R:0  HW:0  E:0%  U:0.0/m

Tonight was the first time I have seen it crash and give this error message, but it's in its third motherboard.  Not sure why this particular card is an issue.  I've got 6 other various cards that have all worked flawlessly. 

I have futzed with this card every way I know how and consulted the almighty Google gods for advice on numerous occasions.  My next step I think is to burn it.  Or nuke it from orbit.  It's the only way to be sure.

That particular message is for thread concurrency. I usually run my two 7850's at 4096 at intensity 12. For any higher intensity, 8192.

I had a similar sort of problem with a 7950 where it would only mine at 80 kh at intensity 19. It turned out that the card was stuck at idle clock speeds even when running cgminer. With the drivers I was using, I needed a monitor plugged in to get it to run at full speed. Can you check your clock speeds to make sure this isn't happening?

[/quote]
That particular message is for thread concurrency. I usually run my two 7850's at 4096 at intensity 12. For any higher intensity, 8192.
[/quote]

Thanks for your input.  I just tried 4096 intensity 12 and same crash.   :(

Hi thanks.  I have it plugged into my monitor at the moment.  Working fine.  It also benchmarks pretty well compared to my other two 7850's so I believe it to be running at default clocks.  Using AMD 13.4 drivers, Sapphire Trixx utility, and GPU-Z.

big daddy WOO WOO~!

sorry to hear your troubles...

Sometimes my cards do the same, I run thread concurrency 8192 and the intensity of 17 on second card and 13 on the main card.

Usually a few restarts fixes it, I find when its got the low hash the GPU usage is 100% where as when they are working correctly its 98-99% usage.

I would look into drivers first of all, strip off all drivers and install fresh. Also I find stopping the miner and changing the clock speed slightly using the overclock tool and starting miner again fixes it.

Hello Mr. Balls sir how's it going? Or should I call you Masta donut?  Where you been lately?

Yep I think this one's about to go up on ebay.  It would make someone a fine gaming card or bitcoin miner but I'm all WDC so it's doing me no good.  I have built and rebuilt rigs trying to get this card to work for me but I am tired of trying. The funny thing about it is I tried finding something wrong with it either benchmarking or gaming wise and I have been unable to.  It's rock solid in that regard.