Bitcoin Forum

Hi guys.

I want to share with you my experience getting Sapphire HD 7970 over 700kh/s. I have 4 of these cards on my rig and i was struggling almost a two months to achieve 700kh/s. Yesterday i finally did it. First thing i want to say is that i tried many different configurations from many threads on this forum and elsewhere, but unfortunatelly, non of them worked fine for me (but i have learned many things from them, that help my solve my problem)

I was getting 520kh/s per card, with 1010/1375/1.025 (engine/memory/voltage) - when i was buying that cards i was expecting something about 720kh/s.

My settings in CGMiner was --thread-concurrency 8192 -I 13 -w 256. I read somewhere that thread-concurrency for 7970s should by around 24000 of less. But i was unable to get above 8192. When I tried to set higher value CGMiner reported some error message with buffer - i dont remmember that exactly. Almost the same when I set higher intensity. With overclocking i could get only ~560kh/s. The 0.5 - 0.65 engine/memory ratio did not work for me. Example from SCRYPT-README.txt did not work for me neither. -g 2 makes me hashrate drop down... Well, i was desperate  ???


After some time I have found a post saying that I should have at least the same amount of system ram as i have gpu ram for scrypt mining and that system ram matters with scrypt. (It is actually written in CGMiners SCRYPT-README.txt - if I just read it from beginning to end, i should save so much trouble...) That time i had only 2gb of system ram, and each Sapphire HD 7970 has 3gb. I does not take long and I bought 8gb ddr3 ram. It makes a difference! Finally i was able to set higher thread-concurrency values. With that i could try again 7970 tuning example for SCRYPT-README.txt. The default thread-concurrency for me is now 22400 and worksize 256. My hash "skyrocket" to 540kh/s  ;D Not what i have expected. But with this new ram i was able to set higher intensity. So with -I 20 i was getting around 600kh/s. That was better. With memory overclocked to 1500 i was getting 660kh/s. That was much better! But still - friend of mine was getting 720kh/s with the same card, with no problems. He just connected his fresh new card to his motherboard and it give him 700kh/s just like that  :o Damn, Lucky bastard  ;) But i did not give up.

I after reading some articles about 7970 overclocking i finally did what i was afraid to do. I change voltage. That brings whole new dimension to my overclocking. Now i was able to overclock memory above 1500 - to that numbers i saw so often in posts from other users. But it was no use. Even with memory to 1700 and engine to 1100 i was getting even lower hashrate that with defaults. I went back to 1500Mhz for memory. I tried to go up in little steps but when i went to 1501 - hashrate drops. I tried to go down a hash rate was relatively stable. It was almost stable within range 1450-1500Mhz - just few kh/s difference. I leave it on 1500 and i start to change engine clock. By the way my voltage was 1.135. I have started at Memory/2 Mhz and went up in 5Mhz steps. Hashrate was slowly growing but it was not significant. I passed 0.6 ratio and hashrate was still low. I start making bigger steps and when i was around 1000Mhz I was at 670kh/s. With 1030 i was at 693kh/s and finally with 1040 i was at 700kh/s. What a feeling!  :P I went up to 1100Mhz with ~730kh/s. I think if i change a voltage a bit higher and continue to going up with engine clock it could be even more, but i have stopped there because the power drain was to high. After that i was lowering voltage and trying to find lowest stable value. It was around 1.080V.

I have tried all 4 cards at this settings but power output was ~1150W (I have 1200W 80Plus Gold PSU). That was to high for me. I lower the settings to 1060/1500/1.065 and power output was ~1075W and hashrate ~715kh/s. Again, I went down for a bit just to take load from my PSU and i ended at 1040/1470/1.050 with ~700kh/s and ~1020W. So the engine/memory ratio in my case is 0.707 or higher. I mine with this settings over 24 hours now and it is pretty stable. Temperature is little higher but that is expected with higer voltage.


I am so happy i did it over 700kh/s with these cards :) and i hope my experience can help at least some of you, fighting the same fight i did. I hope it was not boring and I am sorry for my defective english. To complete my post here is my pc configuration and some pictures

Motherboard: ASROCK 970 Extreme4
GPUs: AMD Radeon HD 7970 (Tahiti XT) (925MHz), 3GB DDR5 (5500MHz)
RAM: Crucial 8GB DDR3 1600MHz CL9 Ballistix Sport
CPU: AMD Phenom X2 545
PSU: Fortron Aurum Pro 1200W

Windows 7 64bit Professional
CGMiner 3.1.1
Drivers 12.8
APP SDK 2.7

http://oi39.tinypic.com/2qdud5k.jpg

http://oi39.tinypic.com/2zz1g1l.jpg

http://oi44.tinypic.com/f1hbom.jpg

THANK YOU!!!!!!!!!!!!!!!!!!!!!

This finally worked for me, got me slightly over 700!!!!!!!!!!!!!!!

Defective English? You did great! Post this in the newbies/mining threads and watch the love pour out :)

what are your final configuration cgminer? Bring your entire line of .bat file. I mean

cgminer --scrypt -o pool -p .... and  further

I'm still fighting this fight!

You mention you have 2g of system ram that went up to 10g of system ram but isn't this still lower than the GPUs ram? If you have four 7970s with 3g each isn't that 12?

I current'y have 12 gigs of GPU ram and only 4gigs of ram on my mobo. Looks like I should upgrade, but I'm not sure how much to get.

You are welcome, I am glad it helped you! Looking forward to your donation  ;D
What fixed your problem?


Thank you

cgminer --scrypt -o ... -u ... -p ... -o ... -u ... -p ... --no-submit-stale -I 20 --lookup-gap 2 --gpu-vddc 1.050 --gpu-memclock 1470 --gpu-engine 1040 --gpu-fan 100 --temp-cutoff 85

No i have 8gb of system ram in total, not 10. As far as I understand it, you need to have more system ram then your one GPU has.

And all? You will not expose in a row is thread-concurrency, -g 2 and -w 256?

-g 2 for intensity 20 is crazy. It's probably -g 1

i've managed to get my sapphire hd 7970 to 750 khash/sec :)

using the following :

--expiry 1 --scan-time 1 --queue 0 --gpu-engine 1090 --gpu-memclock 1500 --shaders 2048 --thread-concurrency 8192 -I 13 -g 2 -w 256 --lookup-gap 2 --no-submit-stale

http://img694.imageshack.us/img694/8931/7970750khashmining.jpg (http://imageshack.us/photo/my-images/694/7970750khashmining.jpg/)

MAN you are awseome!!!  I was getting 730s with 1050/1500, your 1090/1500 totally boosts it up!!!  THANKS :D

It's giving me 760s in Win8 ;)  Now I have to see how low I can get the voltage with 1090.

Try removing --shaders and just leave thread concurrency.  It gives a boost

You are going to wear your card fans out quickly by setting your GPU fan at 100%.  If you are having that much of a problem with GPU temps you should get an external fan to improve air flow between the cards and reduce ambient temperature.  It will make a difference.

Back down on the settings a bit. Your temp. isn't good for long term mining. You'll wear your card out quickly.

All. Thread-concurrency is by default 22400, -g default -w 256 by default

High temps yes, but the fan speed has nothing to do with card lifespan.

No but high fan speeds can reduce the lifespan of your FAN.

It'll eventually become loose, noisy, etc. and you'll have to replace it.

Yes, that is what I meant.  Fixed the typo.

So if my cards are 3g does having 4g of system ram make it enough assuming I have four 3g cards?

As far as I know Reaper is the only mining app that requires a lot of ram.

My 6x 7970s with cgminer use 325MB of system ram.  This is on a system that currently has 16GB of ram.

Yes i think it is enough. But if you have opportunity to add more ram for free just for test - try it. If it helps - buy it

Cgminer itself does not use lots of ram indeed, however you DO need that large amount of ram just to create the buffers to speak to the GPU, even if they don't show up as used ram.

Currently there is no other way. I have to tame the warmest GPU. I have 3x12cm at 1500rpm fans blowing air into GPUs, but with this temps outside, it's mission impossible to keep them cold. Currently I am thinking about buying water cooling system, so I hope that the fans will last until such time as I decide.

http://oi41.tinypic.com/30ti4nc.jpg

you know, you could just space out your gpu's a bit further apart and stagger them

I'm not letting it run above 75°C for most of the day, i just lowered the fan speed because i had visitors sitting next to me (which is also pretty much next to that card hashing away) :)

What is the proper amounts we are looking for if you don't mind me asking? I currently have a system with 4x7970s that each have 3GB of ram on them. Would we need a 1:1 of GPU ram to SYS ram?

at this profitablity,i prefer the higher p/w  ::)
http://nx2.upanh.com/b1.s29.d3/d70dd279997c9f18f44b8491e46b4ab2_56204112.79702.jpg
680Khash and 0.981Volt
it's about 170W per card  ;D ~ 4khash/1W

ckolivas,


Could you elaborate? Are you saying you need minimum 3GB of system ram if you're running a/multiple video cards which have 3GB VRAM each? Or would you recommend having 3GB for each card? Say 12GB of system RAM for 4x 3GB VRAM video cards?

Personally I'm running a few rigs with 6x 7970s in each, all at 740KH/s per card. Rigs have either 4GB DDR3 or 6GB DDR3 and I've had zero issues.

I was planning to turn the rig into a dedicated unit this week since it's my main rig right now and throw 4GB of ram on it, so you think that won't be enough for 6x7970s?  

It isn't a question of the RAM the mining software uses, but the memory required by the algorithm the coin uses.  SHA-256 (Bitcoin) does not require a large amount of memory to hash efficiently, while Scrypt (Litecoin) does.

I can't seem to get my 7970 card to mine correctly.  I have two cards in the same box and one is hashing at 520mhs and the other is 575 mhs. 

I tried the following settings:  --expiry 1 --scan-time 1 --queue 0 --gpu-engine 1090 --gpu-memclock 1500 --shaders 2048 --thread-concurrency 8192 -I 13 -g 2 -w 256 --lookup-gap 2 --no-submit-stale


Do I need to change the settings in Afterburner also?  Or will Cgminer just do it.  I have 8 Gb ram.  Also why does one card hash less than the other?

Thanks

I currently have a machine with 4x7970 Vapor-X's.

I ran a quick/dirty test per what ckolias said;

4gb    2.348Mh/s    30m
8gb    2.338Mh/s    30m
         2.353Mh/s    60m

As you can see I didn't really notice much of a difference going ffom 4gb to 8gb. Am I supposed to have 12gb?

You guys are right.  I set up two dedicated rigs today taking all the cards off my main rig and put 4GB RAM on each. The rig with 6 7970s would not mine all cards.  It would only do 2-3 at a time.  I was worried something broke.  I even re-imaged the operating system.  Then what you guys said occurred to me.  I put 8GB on the big rig and now all 6 cards can mine again. using scrypt.

8GB will do 6 7970s using tc-8192 with full speed hashrate, which is perfect since that's all that is needed on these cards. But just for test, I noticed I couldn't go higher than 8192 like I was able to do on the machine with 16GB. Just something for anyone else to keep in mind. Mainly with lots of 7950s I know you guys use high thread concurrency, how much ram are you using with high thread concurrency and 5-6 cards? More than 8GB?

Very awesome :D

I have almost the exact same setup as the OP, only thing different is the brand of ram he's using. I get the same hashrates but when intensity is over 13 the shares are never accepted by the pool. Shares just show up in the HW section of cgminer. With I 13 I can't seem to get ever 600kh. I've tried the cards in a differn't pc, same result. I haven't been able to find the driver and sdk version the OP is using though.

12.8 drivers : http://forums.guru3d.com/showthread.php?t=367183

APP SDK 2.7 : http://developer.amd.com/tools-and-sdks/heterogeneous-computing/amd-accelerated-parallel-processing-app-sdk/downloads/download-archive/  (scroll down once or twice, you'll see 2.7 for different OSes)