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How to fine tune Radeon 7970 / R9 280X on CGMiner

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How to fine tune Radeon 7970 / R9 280X on CGMiner

How to fine tune Radeon 7970 / R9 280X on CGMiner

How-to-fine-tune-a-Radeon-7970-R9-280X-on-CGMiner

Once you have decided to venture into crypto-currency mining and have set up a mining rig, it takes time to fine tune your machine in order to have a better hashrate. I would assume that you have known the basics of Litecoin mining to be reading this, so i will not waste much of your time on the history of crypto-currency and go straight into tweaking the values in CGMiner in order to have a higher hashrate output.

 

Tuning an AMD Radeon 7970

Example tuning a 7970 for Scrypt mining taken directly from the creator of CGMiner:

In the same console/bash/dos prompt/bat file/whatever you want to call it, before running CGMiner,

  • On Linux use this command:

export GPU_MAX_ALLOC_PERCENT=100

  • On Windows use this command:

setx GPU_MAX_ALLOC_PERCENT 100

 

 Step 1 : --thread-concurrency

  • First, find the highest thread concurrency that you can start it at. They should all start at 8192 but some will go up to 3 times that. Don’t go too high on the intensity while testing and don’t change gpu threads. If you cannot go above 8192, don’t fret as you can still get a high hashrate.
  • Delete any .bin files so you’re starting from scratch and see what bins get generated.
  • First try without any thread concurrency or even shaders, as cgminer will try to find an optimal value :

cgminer -I 13

  •  If that starts mining, see what bin was generated, it is likely the largest meaningful TC you can set.

Starting it on mine I get:

scrypt130302Tahitiglg2tc22392w64l8.bin

  • See tc22392 that’s telling you what thread concurrency it was. It should start without TC parameters, but you never know. So if it doesn’t, start with --thread-concurrency 8192 and add 2048 to it at a time till you find the highest value it will start successfully at.

 

Step 2 :  --gpu-memclock

Then start overclocking the eyeballs off your memory, as 7970s are exquisitely sensitive to memory speed and amazingly overclockable but please make sure it keeps adequately cooled with –auto-fan! Do it while it’s running from the GPU menu. Go up by 25 at a time every 30 seconds or so until your GPU crashes. Then reboot and start it 25 lower as a rough start. Mine runs stable at 1900 memory without overvolting. Overvolting is the only thing that can actually damage your GPU so I wouldn’t recommend it at all.

 

Step 3 : --gpu-engine

Once you find the maximum memory clock speed, you need to find the sweet spot engine clock speed that matches it. It’s a fine line where one more MHz will make the hashrate drop by 20%. It’s somewhere in the .57 – 0.6 ratio range. Start your engine clock speed at half your memory clock speed and then increase it by 5 at a time. The hashrate should climb a little each rise in engine speed and then suddenly drop above a certain value. Decrease it by 1 then until you find it climbs dramatically. If your engine clock speed cannot get that high without crashing the GPU, you will have to use a lower memclock.

 

Step 4 : Final tweaking

Then, and only then, bother trying to increase intensity further.

 

My final settings were:

--gpu-engine 1141 --gpu-memclock 1875 -I 20

for a hashrate of 745kH.

 

Note: I did not bother setting a thread concurrency. Once you have the magic endpoint, look at what tc was chosen by the bin file generated and then hard code that in next time (eg --thread-concurrency 22392) as slight changes in thread concurrency will happen every time if you don’t specify one, and the tc to clock ratios are critical!

 

Good luck, and if this doesn’t work for you, well same old magic discussion applies, I cannot debug every hardware combo out there. Your numbers will be your numbers depending on your hardware combination and OS, so don’t expect to get exactly the same results!

 

 
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Article details
Article ID: 21
Category: Crypto Currency
Date added: 2014-01-16 01:48:08
Views: 401
Rating (Votes): Article rated 3.0/5.0 (8)

 
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