Bitcoin Forum

Hi All,

I have 2 7950 (Sapphire 11196-09-40G HD7950 3GB Vapox-X Graphics Card) cards and my entire system configuration is given below.

The problem is initially while starting the mining task the hash rate is between 1060kh/s and 1080kh/s. But 4 to 5 hours later the hash rate is getting reduced and sometimes dropping to 880kh/s

Can anyone help me in solving this problem.

Mining Software :

• Reaper

System Configuration:

• Asrock Socket AM3+ 970 Extreme4 5200MT/S Motherboard

• Corsair AX Series AX860 860W Platinum Power Supply

• Sapphire 11196-09-40G HD7950 3GB Vapox-X Graphics Card (2)

• AMD SDX145HBGMBOX Sempron 145 Single-Core Energy Efficient Processor

• Generic Hard Disk Drive 320GB SATA 3.5"

• Corsair CMX8GX3M2A1600C9 XMS3 8GB (2x4GB) DDR3 1600 Mhz CL9 Performance Desktop Memory Kit

• Sharkoon T9 ATX Midi Tower Case - Red

GPU 1 and 2 TRIXX Information:

https://i.imgur.com/H3FuORZ.png

GPU 1 and 2 TRIXX Overclocking Settings :

https://i.imgur.com/nSd161e.png

GPU 1 and 2 TechPowerUP GPU-Z Graphics Card Details :

https://i.imgur.com/DIfmzyQ.png

GPU 1 and 2 TechPowerUP GPU-Z Sensor Details :

https://i.imgur.com/8Yb4Ddx.png

GPU 1 and 2 Mining Details :

https://i.imgur.com/YyNmbFw.png

Coin conf Settings:

worksize 256 ; aggression 18 ; threads_per_gpu 1 ; sharethreads 18 ; lookup_gap 2 ; gpu_thread_concurrency 20992

Reaper Conf Settings :

kernel reaper.cl
save_binaries yes
enable_graceful_shutdown no
long_polling yes
device 0
device 1

Maybe the VRM is overheating i had the same problem with my card or you are getting HW errors due to higher intensity. I suggest you try cgminer instead of reaper and with settings -g2 -thread-concurreny 8192 -I 13

I tired CGMiner

When I start cgminer I am getting the error "cgminer.exe has stopped working" .
I am using Windows 8 Professional 64 bit Opperating System

That's probably because you used a wrong thread concurrency number.

Make a .bat file and enter the following text to try it out


For pool, use whatever pool you are mining at.

Whether also I need to have the conf file or its just enough to create a .bat file with these settings and use it.
 As I dont have that with me.

Also I am doing solo mining for paycoin now. So will it work for scrypt solo mining

your gpu temperature is too high, so your gpu down clock. Thats the problem.

You dont need config file. Just create a .bat file and enter that. It works for scrypt mining since you have the --scrypt tag in the line i gave you.

the problem he is having is that the gpus don't run at 99% all the time they sit lower than that ( I used furmark to test and gpu usage still dosent hit 99%

OP, try adding this line to your cgminer config:
--gpu-powertune 20


Looking at your VDDC values in GPU-Z before and after your miner started it seems like some of your card voltages are being down tuned.  This is a common feature on AMD cards to help prevent overheating. By pushing the powertune up to max it should help keep your hashes remain stable over time.

And I would suggest cgminer 3.3.1 as a good replacement miner for reaper. 

That is probably due to overheating since you have your cards in a case. Look at that VRM value after a couple of hours of running cgminer. Try with an open case for testing purposes or smth.

its not the temps as its still the same when fans are at 100% and the cards are a lot cooler

its not the voltage as its just voltage sag and its the same as all other rigs I have made

its not power tune as I have tested that

its not the overclock as I have tried it without

its not the psu ( ax860 )


( I built the rig for him and it got damaged in the post he had it repaired now it does this )

One of my rigs is a bit unstable and if left to run 24/7 will eventually end up with a card that reads sick or dead.

I fixed this by scheduling a reboot every 3 hours and setting cgminer to auto start at boot. This has completely cured the problem. I suggest similar measures.

thanks but the problem he is having is that the cards wont sit at 99% they sit at around 90% after only 1 or 2 mins

I have never had it happen before and I have made lots of rigs

I opened both the side doors in the case and tried it. But still the problem occurs