Mining Litecoin on the Radeon 7970: The quest for 700kh/s

Here I am again with another post, wow.   This time I want to talk about Litecoin.  I’m sure most of you have heard of Bitcoin,  Litecoin is similar to Bitcoin and is just another form of Digital Currency.  I’m writing this with the assumption that you are familiar with “mining” and that you are here because you have a 7970 you are trying to mine with.  I’ve spent some time trying to get a decent hash rate out of the PowerColor HD7970 V3 I bought a couple of weeks ago and have laid out how I was able to get 700kh/s+ out of it below.

First let me say I would not recommend buying this card to mine with.  It’s stock cooling solution  is weak and you will never get the ram clocked high enough without a decent cooler.  You are better off going with a card that comes with a good stock cooling design.  I put an Arctic Xtreme 7970 on my PowerColor v3 and it seems to be doing a fairly decent job; my only real complaint would be that the cooler extends the length of the card so it’s likely going to be a hassle to install in a case that’s cramped.

After getting the cooler attached I started my quest to find a “Ghz” edition bios that would work.  Again, this is not a reference card so not every bios is going to work and I was unable to find anything pointing me in the right direction.  So with a little detective work, I was able to figure out that the Club 3D Royal Queen 7970 is based on the same board (LF R19FD) and it’s Ghz edition bios seems to work just fine on the PowerColor HD7970 V3.  You can find it at the techPowerUp GPU Database.  The Ghz edition bios seems to help achieve the 700+ kh/s rate these 7970 cards are known for.

I flashed the Ghz edition bios and set on my quest to unlock the mystery of the core/mem ratio.  The stock ratio is probably _not_ going to get you anywhere near the 700kh/s mark.   I spent some time going over forum posts and the SCRYPT-README for cgminer where the author of this great piece of Open Source software gives tons of solid advice about overclocking / tuning a 7970 for scrypt mining.  Building upon that I set out to find the highest  hash rate I could on my setup  by maxing out my memory frequency and adjusting the core clock until I found a rate that was getting me close to what I wanted to see.

Adjusting the core clock -/+ 1 mhz from the base ratio of .57 – 6 suggested in the SCRYPT-README I found that the optimal  ratio for my core clock and memory clock was “0.60835820895″.  Multiplying that by the memory frequency of 1775 suggests a core of 1080 and with that I get ~700kh/s using cgminer –lookup-gap 2 -I 13 –thread-concurrency 8192 -g 2.

Changing the core clock in increments of 1 up and down a few values from that  is worthwhile as I have observed all it seems to take is 1mhz to shed hashes from your rate.  Use the “magic number” as a guide and work from there and hopefully you see some similar results.   I’m using the 13.4 Catalyst drivers and MSI Afterburner to control my clocks but would expect the same results regardless of what method you use for that.  Your Catalyst version will most likely play a factor.

As with anything, your mileage may vary.  Driving a display and mining on the same card is going to affect your hash rate.  Other tasks that utilize your CPU will affect your hash rate and you may find better results if you use core pinning/processor affinity with your mining app.

So the end result of my quest resulted in my being able to get 700kh+ out of a 7970.  If anybody actually reads this and gives that magic number a shot, let me know how it works. :)

 

  1. First, I’d like to say good job on the awesome work you’ve done. I, like you, bought the same card in hopes to do what you’ve already accomplished. I’ll perform the same steps and use the magic number you suggested then report back with the results.
    It’s quite amazing that you’ve figured the ratio to be so exact; kudos for that. I do, however, have some questions that I hope you can help me with.

    What voltage did you use for these cards?
    What’s your current rig setup? Mobo/CPU/RAM/Risers/temps/PSU/#GPUs? Open Air or Closed Case?
    What version of cgminer are you using? Win7/8? 32/64 bit?
    Has the system been stable? If so, how long?
    What version of bios are you using? Club3D.HD7970.3072.120912.rom V.015.022.000.006.000000?

    I tried following the link to techpowerup on your blog but the link was broken. I think the redirect isn’t working.

    Thanks again, I’d be sure to send some coins over if you would also include that in your post as I’m sure others who stumble on this will too.

    • Hi Grim, thanks. I just kept tweaking until I found what seemed to be the best ratio and stuck with it. I had someone try the same number on a different brand card and it didn’t give him as good a results so I suspect different models will have different ratios. My voltage is 1175mV with the power limit set to +20% in Afterburner. As for my system I’m running a first generation i7 920 watercooled and overclocked to 3.53ghz, 24 gigs of ram on Win7 x64. I’ve got a couple 58×0 cards in here as well running in a seperate cgminer process as they don’t play well with the same thread count as the 7970 does. Stability is 100%, I haven’t had a crash or a blue screen with these settings. I’m using the BIOS from http://www.techpowerup.com/vgabios/127298/club3d-hd7970-3072-120912.html I didn’t want to include that link as I didn’t want it to become outdated. Hopefully you get the hash rate you’re looking for, let me know how it turns out. :)

  2. I have a Gigabyte GV-R797OC-3GD 7970.

    With the engine set to 1085 and memory clocked 1500 I can get ~760kh/s.

    @963/1220 I get around 680kh/s and that seems to be a good setting in terms of stability and heat management (I have 5 cards per rig so that’s a major issue).

  3. ok i smashed the 700 mark with my 7970 without even realising it was a “hard” target to get

    i have a Asus HD7970 DC2T and in my quest for a P10k+ 3dmark11 score flashed it with several bioses before finding out that the DC2 bios was perfect :D during this research I also found the tool unlocking 50% power boost (usually 20%) :P

    I could overclock her like anything and having the memory of the DC2T card i was pushing up to 1800mhz and 1250 gpu clock, reaching 11k
    and my best run at 1250 / 1775 was 11100 http://www.3dmark.com/3dm11/6756707

    I had mined previously with a 5770 and a 6950 and thought i’d see how the 7970 went.

    so i switched back to the overclocking bios and had a play. i found a tool, called guiminer (not the sha256 one, but a fork) and it gave me a really good hashrate, it called cgminer from which i was able to write a config file and play from there.

    When running at 1090 with 6000 ram i get 740-755
    with the ram at 7000 i could sometimes get 760
    at 980 6000 i average around the 720 mark, fine by me for my little play

  4. This is great info. Thanks! I started following close the ratio you posted, and so far it’s working great. I lowered my core clocks to 1000mhz and upped my mem to 1700; resulting in a jump from 490-530 to over 650 khash… I think with a little tweeking I’ll get there. Thanks again.

  5. I have a pair of XfX Radeon R9 280′s which are overclocked to 1120mhz gpu 1640mhz Ram and they hash around 604-610k.

    I have a single Gigabyte GV-R797OC-3GD 7970 and it will hash around 696k at 1ghz Gpu 1.5ghz Ram. If I put leave it at stock 1.1ghz the hash rate is irregular and hashes only in the 500′s. However certain days it will hash properly at 1.1ghz and I’ve seen as high as 765k. I think there is something wrong with the card. :/

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