Author Topic: AMD Radeon HD 7850, Cgminer 2.11.4, Ubuntu 12.04 LTS low hash rate  (Read 11787 times)

Offline AZ-Miner

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Is there anyone out there running an AMD Radeon HD 7850 with Cgminer 2.11.4 getting an average hash rate above 224kh/s that can suggest some tweaks to cgminer.conf to increase my hash rate?  I have tried the settings suggested in the mining hardware comparison chart and cannot get anything above 224kh/s.
Running export GPU_MAX_ALLOC_PERCENT=100 prior to running the client seemed to help and have toggled block size from 128 and 256. 256 seems to work best.
The mining hardware comparison chart shows hash rates of 350, 382 & 411 but I can't seem to get above 224. GPU Intensity of 17 slows down the system and this is my primary machine so that's not an option. Any suggestion that helps will be rewarded with 1 LTC for your assistance. Below is my config. Thanks.

"intensity" : "13",
"vectors" : "1",
"worksize" : "256",
"kernel" : "scrypt",
"lookup-gap" : "0",
"thread-concurrency" : "0",
"shaders" : "0",
"gpu-engine" : "0",
"gpu-fan" : "0-85",
"gpu-memclock" : "0",
"gpu-memdiff" : "0",
"gpu-powertune" : "0",
"gpu-vddc" : "0.000",
"temp-cutoff" : "95",
"temp-overheat" : "85",
"temp-target" : "75",
"api-port" : "4028",
"expiry" : "120",
"gpu-dyninterval" : "7",
"gpu-platform" : "0",
"gpu-threads" : "1",
"log" : "5",
"no-pool-disable" : true,
"queue" : "1",
"scan-time" : "60",
"scrypt" : true,
"temp-hysteresis" : "3",
"shares" : "0",
"kernel-path" : "/usr/local/bin"


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Offline fuzznarf

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Re: AMD Radeon HD 7850, Cgminer 2.11.4, Ubuntu 12.04 LTS low hash rate
« Reply #1 on: April 10, 2013, 02:31:39 PM »
i get about 300khs on a reference 7850, 3% undervolt, stock clocks

--thread-concurrency 4096 -g 2 -worksize 256
LTC: LfvVoS9zGeRqXDyKpsvSQNXoyoNBgEeQc6
BTC: 1Bj1xQjQg8eJqZNkuozNEwLN58FYKqzxsz

Offline AZ-Miner

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Re: AMD Radeon HD 7850, Cgminer 2.11.4, Ubuntu 12.04 LTS low hash rate
« Reply #2 on: April 10, 2013, 03:24:47 PM »
i get about 300khs on a reference 7850, 3% undervolt, stock clocks

--thread-concurrency 4096 -g 2 -worksize 256

Thanks but that just gave me hardware errors.

Offline Yurkar

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Re: AMD Radeon HD 7850, Cgminer 2.11.4, Ubuntu 12.04 LTS low hash rate
« Reply #3 on: April 11, 2013, 09:04:28 PM »
For hd7850 "thread-concurrency" value is 8192. It's mandatory and overrides "shaders" option as well. In case you haven't read SCRYPT-README (https://github.com/ckolivas/cgminer/blob/master/SCRYPT-README) carefully - "vectors" option doesn't use with "scrypt" option enabled. Frankly speaking, all you need in your conf file, besides pools, are:

"intensity" : "13",
"thread-concurrency" : "8192",
"scrypt" : true

La4mxRhGGNBMEtv2ht9UPRaymzPdgVnZfv

Offline AZ-Miner

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Re: AMD Radeon HD 7850, Cgminer 2.11.4, Ubuntu 12.04 LTS low hash rate
« Reply #4 on: April 12, 2013, 05:20:09 AM »
For hd7850 "thread-concurrency" value is 8192. It's mandatory and overrides "shaders" option as well. In case you haven't read SCRYPT-README (https://github.com/ckolivas/cgminer/blob/master/SCRYPT-README) carefully - "vectors" option doesn't use with "scrypt" option enabled. Frankly speaking, all you need in your conf file, besides pools, are:

"intensity" : "13",
"thread-concurrency" : "8192",
"scrypt" : true

Thanks that bumped it up about 40kh/s. Sent one LTC to your address. Anyone else have any suggestions?
« Last Edit: April 12, 2013, 06:07:27 AM by gacjr »

Offline Yurkar

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Re: AMD Radeon HD 7850, Cgminer 2.11.4, Ubuntu 12.04 LTS low hash rate
« Reply #5 on: April 12, 2013, 06:49:09 AM »
Unfortunately, you have reached almost maximum at stock clocks and intensity=13 (270-280 Kh/s). For higher performance you have to overclock it and enlarge intensity.
La4mxRhGGNBMEtv2ht9UPRaymzPdgVnZfv

Offline bruiser

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Re: AMD Radeon HD 7850, Cgminer 2.11.4, Ubuntu 12.04 LTS low hash rate
« Reply #6 on: April 12, 2013, 10:18:31 AM »
He's right. I messed with a batch of 7850's and 7870's and the highest I could get was ~270kh/s on the 7850's. Even overclocking didn't give you THAT much more speed, and increased the risk of rejects and stales as well.
The best results I had were literally with intensity 12 or 13. Going higher than that started to drop them--I don't buy the github results as accurate at all. Maybe cgminer was saying "350 kh/s", but they probably had 30% rejects or constant errors. Remember to check your pool and see that its verifying what cgminer says--not always the case.


Offline AZ-Miner

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Re: AMD Radeon HD 7850, Cgminer 2.11.4, Ubuntu 12.04 LTS low hash rate
« Reply #7 on: April 12, 2013, 12:03:09 PM »
He's right. I messed with a batch of 7850's and 7870's and the highest I could get was ~270kh/s on the 7850's. Even overclocking didn't give you THAT much more speed, and increased the risk of rejects and stales as well.
The best results I had were literally with intensity 12 or 13. Going higher than that started to drop them--I don't buy the github results as accurate at all. Maybe cgminer was saying "350 kh/s", but they probably had 30% rejects or constant errors. Remember to check your pool and see that its verifying what cgminer says--not always the case.

Well, I'm getting a steady 271kh/s right now and no HW errors or Rejects when I view in Debug mode so based on what you are saying I'll be happy with that . I have a case and a MoBo with 1 PCI-e slot on it. Just needs a CPU, PU , some RAM, and a GPU and I'll have another worker. Not sure what GPU I want to put in it. Maybe another 7850 hard to decide on that since I can't trust the Github results. Any suggestions? Can't decide whether I want to make the investment in hardware for another worker with LTC down to $1.5 as I post this from almost $5 last week can't justify the expenditure.

Offline bruiser

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Re: AMD Radeon HD 7850, Cgminer 2.11.4, Ubuntu 12.04 LTS low hash rate
« Reply #8 on: April 12, 2013, 01:56:47 PM »
7950 would be my recommendation. 7970's are better, and if you can find them 2nd hand in good condition for ~$350 then they're a really good $/hash buy but be forewarned they are truly a dark art to master their production. Any MSI/Gigabyte(in my experience) 7950 you can run with almost no flags besides maybe intensity and worksize and see ~560-590kh/s with ease.

As far as the price of LTC... I'm willing to stick around. I like the platform. What we need is a much easier USD-->LTC method and also places that offer real, tangible items that accept LTC. There are definitely some in the works, but until then it will track BTC prices as theres not much of a "support network" yet.

Offline soslowso

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Re: AMD Radeon HD 7850, Cgminer 2.11.4, Ubuntu 12.04 LTS low hash rate
« Reply #9 on: April 13, 2013, 05:46:04 AM »
Try OC to 1160/1375. My Asus 7850 with this settings and config like -g 1 -i 20 -tc about 15000 gives me 380kh without hw errors. Without OC and lower intensity i have about 300 kh. I can post exact config later.

Offline Layerz

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Re: AMD Radeon HD 7850, Cgminer 2.11.4, Ubuntu 12.04 LTS low hash rate
« Reply #10 on: April 13, 2013, 06:03:31 AM »
I can attest to this too, I am getting 345kh with a low stale rate on my 7850 (I will add it is factory OC) however I am looking to tweak it up to 380/400 as it is not breaking a sweat atm and I've been stress testing it for a few days.

That is at 8Kish thread concurrency and Intensity 17 using GUI miner on Windows 7, the fan is at 49% and temp about 55-60 degrees C.

Soslowso, yours settings would be greatly appreciated!
Lb9yCk3ycQqQyRa8gmNUnqkw3VMd8FiST5

Offline bruiser

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Re: AMD Radeon HD 7850, Cgminer 2.11.4, Ubuntu 12.04 LTS low hash rate
« Reply #11 on: April 13, 2013, 08:41:23 AM »
GUIMiner does not accurately report stales/rejects. Make sure you are verifying your accepted shares/hash rate via your pool and not just client-side.

Offline roynu

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Re: AMD Radeon HD 7850, Cgminer 2.11.4, Ubuntu 12.04 LTS low hash rate
« Reply #12 on: June 04, 2013, 06:25:12 AM »

Here is my best configuration for HD 7850 on 9.0.2 driver. I expect later drivers may behave differently (for one, 9.1.11 tends to prefer lower intensity).
I get a stable 364 kh/s without hardware errors or excess stale/rejected shares.


export GPU_MAX_ALLOC_PERCENT=100
export GPU_USE_SYNC_OBJECTS=1
./cgminer --config ~/.cgminer/litecoin.conf --default-config ~/.cgminer/litecoin.conf --scrypt -I 20 --gpu-powertune 0 --gpu-engine 1050 --gpu-memclock 1200


- The config file only contains pool information, no other config
- Powertune had no effect on my system,  but it is probably worth playing with.
- Unless you have reason to do otherwise, just let cgminer pick it's own thread concurrency. With GPU_MAX_ALLOC_PERCENT set to 100, cgminer tends to set TC to 14144 on my system.

Offline skel92

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Re: AMD Radeon HD 7850, Cgminer 2.11.4, Ubuntu 12.04 LTS low hash rate
« Reply #13 on: October 18, 2013, 03:19:24 PM »
I'm sitting steady at ~335 kh/s with the following settings:
--thread-concurrency 8192 -I 16 -g 1

GPU settings:
GPU Clock: 900MHz
Memory Clock: 1250 MHz

Fans are at 50% (super quiet)
Temp has never gone above 61 degrees Celcius

Good luck!

Offline odogollie

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Re: AMD Radeon HD 7850, Cgminer 2.11.4, Ubuntu 12.04 LTS low hash rate
« Reply #14 on: February 27, 2014, 08:04:33 AM »
I know this is an old post but I was messing around with my XFX 7850 and I am getting a steady hashrate (~360KH/s) with very few rejects and no hardware errors here is my batch file (Yes I'm running windows but I assume wont affect anything):

-I 20,20 -g 1 -w 256 --gpu-memclock 1250,1350 --gpu-engine 900,1050 --thread-concurrency 15000

Note: the second card I have is an XFX 7870