cgminer 7950 config help pls

[riznarf]

Hi all,

I'm new to this forum and relatively new to altcoin mining, so go easy on me :-)

I recently purchased 2x 7950s and want to put them to use!  I'm using MSI Afterburner to overclock them to 1085/1500 which I understand to be a pretty respectable overclock (with +20% power usage as well)

So, here's my config in cgminer: cgminer.exe --scrypt -o SERVER -u UN -p PW -I 12 -w 256 -g 2

A few things:

1.  Anytime I crank up the intensity past 12, I get serious hardware errors.  Is this weird because most of the people I see mining with similar hardware are seamlessly doing it on I 20.

2. I looked at the .bat output from cg miner and the file name is: scrypt130511Tahitiglg2tc4032w256l4  This means my tc is only 4032?  I thought the minimum was 8000-something?  And does this also mean the intensity is actually only 4?

With these current settings I'm getting about 400kh/s per card, but am aiming for around 500.

Any additional help you guys can provide would be greatly appreciated.

Thanks!

[SP4RK7]

I'm sure from what I've read you should get around 600 k/hash or more from those cards

I have 7870xt which is a very similar card my bat file is

cgminer.exe --scrypt -o SERVER -u WORKERNAME -p XXXX -I 13 -g 2 --thread-concurrency 8192

Try dropping your clock speeds as well, my cards run a lot faster at 850 instead of the 975 they are supposed to run at. Over clocking is not always the way to go

[gyoezoeke]

I've got 2x7950 in my miner machine, they are running at 609/667kH/s. There is a good 'tutorial' in cgminer directory scrypt_readme.txt. You can use it to set up the cards. My .bat file: cgminer.exe  --scrypt --thread-concurrency 19712 -I 20, other settings in cgminer.conf  (gpu/mem 1095/1575)

[Kestrel71]

People who have it set at I 20 will be using g1 not g2 like you have in your cfg. This is also the wrong section to be posting in, alternate currencies is hardly the place for help with mining cfg's.

[riznarf]

I've got 2x7950 in my miner machine, they are running at 609/667kH/s. There is a good 'tutorial' in cgminer directory scrypt_readme.txt. You can use it to set up the cards. My .bat file: cgminer.exe  --scrypt --thread-concurrency 19712 -I 20, other settings in cgminer.conf  (gpu/mem 1095/1575)

Thanks, yeah I went though the readme and pretty much got to where I was before.  Do you think it's maybe thread concurrency that could be causing the problem?  Also, I tried going -g 1 and -I 13 and I was getting a whole lot of HW errors again...any ideas?

I'm sure from what I've read you should get around 600 k/hash or more from those cards

I have 7870xt which is a very similar card my bat file is

cgminer.exe --scrypt -o SERVER -u WORKERNAME -p XXXX -I 13 -g 2 --thread-concurrency 8192

Try dropping your clock speeds as well, my cards run a lot faster at 850 instead of the 975 they are supposed to run at. Over clocking is not always the way to go

I tried dropping the clock to 850mhz and then messed around with it a bit and it significantly lowered my kh/s - but I have heard this before.

[riznarf]

Hey Guys,

So I've made some progress...I upped my mem clock to 1625 mhz, which allowed me to go to -I 13 without any hardware errors.

Here's my line now:

-I 13 -w 256 --shaders 1792 --gpu-engine 1085 --gpu-memclock 1625 --gpu-vddc 1.150 -g 2

I'm sitting around 925kh/s (both gpu's together)...it's better, but still not where I'd like to be.

Another weird thing:
GPU 0 62 degrees, 545 kh/s
GPU 1 76 degrees, 386 kh/s

Any idea why GPU 1 is running so much hotter and slower than GPU 0?

I think -I 13 is right for me, but do you guys have any ideas of how to get to ~600kh/s like I see everyone else at?

Thanks again!!!

[gyoezoeke]

I've got 2x7950 in my miner machine, they are running at 609/667kH/s. There is a good 'tutorial' in cgminer directory scrypt_readme.txt. You can use it to set up the cards. My .bat file: cgminer.exe  --scrypt --thread-concurrency 19712 -I 20, other settings in cgminer.conf  (gpu/mem 1095/1575)

Thanks, yeah I went though the readme and pretty much got to where I was before.  Do you think it's maybe thread concurrency that could be causing the problem?  Also, I tried going -g 1 and -I 13 and I was getting a whole lot of HW errors again...any ideas?

Yes maybe, tc should be as high as possible I think, my cards go I 20 without any problem. You can set tc manually on commandline in .bat, from ~24000 downwards with stepping of number of shaders. If cgminer not starts normally, lower the tc and try to start again, till it starts normally. After that set intensity higher from i 13 to i 20. It must mine at ~600-650kHs/s . Or the card is defective.

[Mortimer452]

I assume you are using Windows?

Run these two command at a DOS prompt:

setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1

These are the best settings I have found for my 4x Sapphire 7950's:

--thread-concurrency 22400 -I 19 -w 256 --gpu-powertune -10

I run core clock at 1100 and mem clock at 1250, rock solid at 640khash, around 2% rejects and temp and under 65* with no additional cooling, just the card's built-in fan, except for one card (top slot) which always runs at 76* for some reason.  

You can run intensity of 20 but I found this has only barely higher khash, results in higher temps and much higher # of rejects.  I been able to reach 690KH on my cards with higher mem/core clock speeds and I=20 but not very stable - cgminer crashes occasionally, 10+% rejects (which effectively reduces your hashrate by 10%) much higher temps and 20% higher power consumption.  I'm very happy at 640khash and not having to worry about it ever crashing or overheating.  I haven't touched it in days.

Anyone running higher than about 650khash on the 7950 needs to check their A: and R: numbers in CGMiner (Accepted and Rejected shares).  Hashrate isn't everything.  If you're running 690kh with 10% rejected shares, you're really only getting about 621kh (10% less than 690) and using WAY more power and WAY more heat than you need to.