Harvester 1 – Rig updates, dual mining, optimize efficiency

A report about the final setup of Harvester 1, I give you some hints to increase performance and efficiency, and a few words about optimal dual mining.

It’s been a while since I gave you an overview of our Ethereum mining rig. During these days I tried to achieve as much manna from it as I can, of course, but I also kept the initial sensible attitude to take care of the expensive components. We’d like to avoid troubles that may come with maintenance occasions and anyway, we still plan for a long run. With this approach I could finish putting the rig together to its 100% shape. This post is just a short(?) update with pictures and also I give you some useful hints below. Stay with me.

Let’s Grill

Harvest1_034Despite the heading, I don’t plan to give you a bbq tutorial, luckily. Last time I mentioned that we plan to place the PSU on the top of a metal grill. Well, as it still hasn’t arrived from eBay, I canceled that order and bought another one at a nearby shop. I’ve cut the necessary edges out to fit with the frame, covered with a piece of black tights and done. Sorry for the poor quality of the pictures, it was late in the night when I was documenting the progress. Briefly, what did I do:

  1. Removed the original safety grill from the PSU by simply unscrewing them.
  2. Shaped the new grill to fit with the frame.
  3. Put tights on it as an additional dust filter.
  4. Placed the PSU on it with its fan facing downward.
  5. Used some cable tie to fasten the PSU to the grill.

You might ask whether it will be able to suck enough air from below, but let me remind you that we use small feet on the frame providing ample gap under it even if we put the machine on the flat ground.

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I also found a 120 mm Papst system fan laying on my shelves, so I thought why wouldn’t I use it too. It gives a little perpendicular air flow. I know it would be better to isolate the two sides of the fan with a panel or something, but to be honest the poor effectiveness doesn’t really matter as the GPUs still run in the rather fair 59-61 Celsius degrees range.

Dual mining

First, let me clarify a common misunderstanding: dual mining does NOT need multiple VGA cards. The concept behind dual mining is to increase the utilization percentage of the GPU. When you mine Ether, a GPU is calculating heavily, sure, but this calculation needs just SOME “parts” of your GPU. There might be other calculation tasks that use OTHER “parts” of the same GPU. Just like your CPU, a GPU can be loaded with multiple tasks the same time. For a moment, think of the GPU-accelerated PhysX during a game. GPU is already busy rendering the graphics while you give it physics calculations. Also, you can start watching an HD movie on your computer and start playing Battlefield 1. You’ll notice that both GPU accelerated task will run smoothly.

Well, if you mine let’s say SiaCoin or Decred beside Ether, it will affect the Ether mining speed, but it can be calibrated really-really easily thanks to Claymore. I tell you how, and by the end of the day you will exploit your GPU resources more efficiently.

Configure your wallets, pool settings and start Claymore. For instance:

EthDcrMiner64.exe -epool eu2.ethermine.org:4444 -ewal 0xb3f095c58ccefe4a596350fbf1397720857f3971.YourRigName -epsw x -dpool stratum+tcp://pasc-eu1.nanopool.org:15555 -dwal 86646-64.32f2d92df2936571.YourRigName -dpsw x -dcoin pasc -dcri 16 -allpools 1 -allcoins 1

This case it’s Ether and PascalCoin with an intensity value of 16 (see bold argument above). The key is this dcri value that tells the miner in what rate should it share the GPU resources. The lower the number the lower priority for the secondary coin.

ClaymoreNow the trick: after you started Claymore, you repeatedly get reports about the current hash rates, right? Just change the intensity with the “+” and “-” keys on your keyboards by 5-10 steps. Wait for the next report and see what you get. You can also press the “s” key to get immediate statistics on the console, but I experienced too inaccurate values so I suggest patiently wait for automatic reports. If you lower the number too much, you will lose too much from the secondary coin in change of very small amount of additional Ethers and vice-versa: if you raise it too high, you’ll notice you get tiny extra secondary hash rate for the secondary coin while you lose too much Ether. Somewhere in the middle you will get a good balance. Then it is worth to check the resulting profit on WhatToMine. When you found the desired optimum, don’t forget to update your batch file to start your miner with the given intensity value. Briefly:

  1. Choose your coins.
  2. Setup wallets and mining pools.
  3. Update your batch file to mine both of them.
  4. Play with the “+” and “-” keys to find the best dcri value.
  5. Use a calculator to check which rates give you the best profit.
  6. Update the -dcri parameter in your batch file.

Please keep in mind that the optimal intensity value depends on several factors, like the GPU brand (AMD/NVIDIA), the GPU model (GTX 1070/1060/etc.), the clock frequencies, the complexity of secondary currency’s calculations (Pascal/Decred/etc.), the actual exchange rate of the currencies and so on. So it’s a game you have to spend your time with. For our 6x GTX 1070 excavator the best dcri value now is 30 resulting 182/1820 MH/s rates with Ether and Decred respectively. This way I lost around 10 USD/month as I decreased the 187 MH/s to 182 on the Ether side, but got 1820 MH/s from the Decred calculations giving back 30 USD (the profit changes constantly by the exchange rates). The interesting part is that this comes with almost invisible amount of extra consumption on a GTX 1070. While I was playing with my Radeon RX480, it performed much better, I could achieve above 1000 MH/s of Decred without touching the Ether rates. On a single RX480. Unfortunately I had no opportunity to check the consumption delta on that.

Briefly with GTX 1070 cards using Claymore v9.7:

  1. -dcri 30
  2. Ether: 182 MH/s
  3. Decred: 1820 MH/s
  4. Extra profit/month: 20 USD (plus the advantage that we hold our money diversified in more currencies)
  5. Extra consumption: under 2 Watts

Best performance-watt ratio

afterburnI usually run into berserkers on forums who claim the miners just stress the sh*t out of their cards to get the best performance and thus it’s not recommended to buy a VGA from these mine-waders. We, miners should know that by watching the performance only can lead to a rather poor profit, we must not forget about the consumption. We have only 2 numbers to look after to optimize the long-term profit after we have chosen our favorite currency: the hash rates and the power consumption. So it’s inevitably important to minimize the latter while keeping the performance at a high level.

All of you, dear miner friends who approach this subject the same way, I’ll give you a general guide how to achieve the optimal operation:

  1. Install and run MSI Afterburner.
  2. Start the miner program.
  3. Find the highest RAM frequency that is stable and gives you no failed shares. The console helps you in that. For a GTX 1070 it’s somewhere around +600 MHz effective. With RX4/580 cards it should be around 2200.
  4. Check the hash rates you get in the console window.
  5. Now start decreasing the TDP (aka. Power Limit) values.
  6. Repeat it until you see more than 2-3% of hash rate decrease.
  7. Stop there, you got it.
  8. Save the frequencies into a profile in Afterburner and turn on applying the settings on next boot.

You can also play with the GPU frequency (aka. engine clock) by decreasing it manually until it affects the performance, however the reduced power limit does this job automatically. As a result you will see a fair amount of Watts saved for a little sacrifice. Just check your profits in any of the calculators out there. Also you’ll get cooler GPUs, enhanced life-time of VGA cards and a bit less noise. Deal?

If you notice some mistakes or inaccuracies, just let me know in the comments below or drop me a mail. I hope I could help you to increase the efficiency and life-time of your rig. May the Gold be with you!

etherYou can support me to spend my time sharing useful hints like these above by sliding a few coin in my pocket. I really appreciate it.

  • Bitcoin: 3FHWTQJcXneqoyPyFajkv5tRHnB1zhFbGG
  • Ether: 0x57A0ac917775D1dfEe5D7e551BE145bb57b49724
  • ZCash: t1TccE92FHfLQXaZnJBssXgMSE5nNNh2HBa

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