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Bitcoin Currency and GPU Mining Performance Comparison

Author: Ryan Shrout
Manufacturer: General

The Beast - Bitcoin Mining Powerhouse

If you wanted some impressive numbers for Bitcoin mining, you have come to the right place.  The Beast is a rig build around a Core i7 processor and motherboard and 5 GPUs working in tandem off of a single power supply. 

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Here you can see three cards lining up to be utilized for profit computing: the Radeon HD 6990, Radeon HD 5970 and Radeon HD 6970.  With a total of 5 GPUs in this configuration we were really pushing the boundaries of our power supply and office air conditioning.  

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This screen grab shows you the 5 GPUs at work and the impressive (and dangerous) temperatures as a result.  The HD 6990 card GPUs actually hit the 103 degree Celsius mark!  Power consumption on this combination peaked at 1067 watts which actually tells how well built the Corsair AX1200 power supply is!  The cards got HOT very quickly and the fans were spinning a much higher rate than we are used to.  While the configuration did work for a while in our test bed I would not recommend anyone with a sane mindset build it for actual 24/7 usage. 

So, let's look at some of the performance results from "The Beast"!

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Pushing nearly 1.6 Ghash/s, The Beast nearly doubles the performance of the overclocked ASUS ARES card.

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Somewhat surprisingly, even at an estimated cost of $1710, the GPUs on The Beast were a better value than most of our other configurations and were only bested by the HD 5750, HD 5830 and HD 6850. 

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So, yes, The Beast used about 1067 watts during peak power consumption but in terms of performance per watt, again it impressed us by coming in second in this metric!  The use of a pair of dual-GPU cards seems to be helping it out as those appeared to be the most power-efficient options. 

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As expected The Beast earns the most with just about $14.65 entering into your virtual wallet every 24 hours.

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So it cost you $1710 to buy the cards but how long until you pay it off at that rate?  A surprisingly modest 116+ days.

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Because of the high cost of the ARES relative to other dual-GPU cards, The Beast is able to out gain the overclocked version of it by a factor of 2.18x with a potential profit of $3,637 per year AFTER paying off your $1,710 investment.  

When we first decided to build The Beast for this article we thought it would definitely be an outlier in the performance metrics with that much power but we also though it would be way to power hungry and costly to make sense.  That wasn't really the case though - not only did we reach 1.6 Ghash/s but the power consumption and costs, though very high, were actually better than expected in relation to that performance.  This indicates the hashing and SHA256 key creation process scales VERY close to linearly on these GPUs; something gaming rarely does.

July 12, 2011 | 08:26 PM - Posted by Adster (not verified)

Any reason the AMD 6950 & 6970 cards was left out of the experiment? As the flagship AMD single GPU cards, I think this data would be really salient. Is there another card on the list from which we could easily extrapolate 6950/6970 performance?

July 12, 2011 | 10:06 PM - Posted by Tim Verry

In my personal testing, the 6950 gets somewhere around 340 mhash/s with a few optimizations. Overclocking and unlocking can get you around 400. You can get the 6950/70 performance by dividing the results of the 6990 GPU results in the graph.

My understanding of the GPUs used were based on what was available in house for testing.

July 12, 2011 | 10:12 PM - Posted by Tim Verry

More specific results (please keep in mind that I am using different settings than Ken so they are not necessarily comparable):

My 6950 unlocked to 6970 shaders at 840 core gets 372.7 mhash/s using GUIMiner, and two kernel tweaks of the poclbm kernel, and AMD Cat 1.7 drivers and whatever version of Stream SDK comes with that. I'm further using the following flags which are gfx card version specific: -k poclbm VECTORS BFI_INT AGGRESSION=9 WORKSIZE=128

Hope it helps :) If you have any questions please feel free to ask.

July 13, 2011 | 07:22 AM - Posted by Adster (not verified)

Hi Tim,

I'd be interested in a little more information. I'm running a Sapphire 6950 2GB with unlocked (6970) shaders (but not flashed to 6970 speeds; I just OC when I need the boost). I'm also sporting a Core2Duo E8400 OC'd to 3.6 Ghz. I started mining last night, following the guides Ryan mentioned, and I'm consistently getting 320 Mhash/s, not the 340 you mentioned was possible with a few "optimizations."

Do you know if the optimizations you mentioned (the flags) should work for my 6950; you said they are gfx card version specific - did you mean vendor specific, or just 6950 specific? Is it possible to use those flags when I'm using the GUIMiner, or do I need to be using a console? Thanks for any input!

July 13, 2011 | 01:22 PM - Posted by Tim Verry

Hi Adster, I am running a XFX 6950 2GB card with an edited BIOS to have unlocked shaders but not 6970 speeds (though the card is capable of running at them, I didn't want to risk running the memory at the higher speed full time).

The flags that I mentioned will work for you 6950, they are specific to the version of card you have, in this case these flags are best used with AMD 6xxx series cards. You can set the flags in the GUIMiner extra flags area; however, you will need to edit the poclbm kernel file for the other optimizations. You can find those by searching the bitcoin forums for kernel optimizations.

I hope it helps, let me know if you need any help in sqeezing all the mhash possible outta that card :)

April 20, 2013 | 04:47 PM - Posted by Anonymous (not verified)

I have Gigabyte 6950 and overclocked at 900mhz it has 370MH/s , sometimes goes over, but constantly is 370MH/s, it is good for cost effective?

July 21, 2011 | 07:20 AM - Posted by Ukprotect (not verified)

My HD 6950 achieves 362 Mhash/s, I use the following config:
The HD6950 is flashed with 6970 bios, GUIMiner, flags: -v -w128 -f1, Core Clock=890, Memory Clock=1580, PCI-E x16.

August 25, 2011 | 08:44 AM - Posted by Doc (not verified)

I am running an Asus 6950 with the shaders unlock but not the 6970 bios. I am achieving 379 Mhash/s.

I am running phoenix miner 1.6.2 from a command line (guiminer's front end eats Mhash/s). My switches are -k phatk2 VECTORS BFI_INT AGGRESSION=13 worksize=128 FASTLOOP=false

Also I am running it OCed to 840MHz and the memory underclocked to 750MHz. It seems odd, but underclocking the memory adds another 1-2 Mhash/s.

July 13, 2011 | 08:27 AM - Posted by Ryan Shrout

Honestly, we just didn't test it because we skipped some cards. Looking back, we should have done one of them. You can see on our screenshot of "The Beast" that we eventually plugged one in and got about ~ 344 Mhash/s.

July 16, 2011 | 07:16 AM - Posted by Touche (not verified)

Try here for a lits of cards and their Bitcoin potential : https://en.bitcoin.it/wiki/Mining_hardware_comparison

July 12, 2011 | 09:08 PM - Posted by undersea

OK, who is doing this?

July 12, 2011 | 10:07 PM - Posted by Tim Verry

who is doing what? mining?

July 14, 2011 | 09:01 AM - Posted by Anonymous (not verified)

The Chilean miners, they are doing this for sure...

July 12, 2011 | 11:12 PM - Posted by Anonymous (not verified)

don't count on unlocking a 6950 to a 6970 unless you get n older one. ATI/AMD is crippling the new ones.

July 13, 2011 | 08:42 AM - Posted by neliz (not verified)

No they're not, whoever gave you that idea? NV?

July 13, 2011 | 10:01 AM - Posted by Adster (not verified)

This is a great article, and pushed me over the edge to start mining. The only big question I have (aside from my earlier question about 6950/6970 performance), is how the cost of electricity factors in.

Obviously we are all subject to different utility rates, so you couldn't give a cost-breakdown that would apply to everyone. However, I am curious how much the average cost of electricity would deduct from the profits in your chart?

July 13, 2011 | 03:30 PM - Posted by Tim Verry

Hi Adster, stay tuned to PC Per for that info ;)

July 13, 2011 | 07:09 PM - Posted by Bolas (not verified)

Is it possible to mine bitcoins in using Windows7 64-bit, or do I have to install Linux?

Does the amount of system memory matter when mining bitcoins, or is the graphics card the only real limiting factor?

July 13, 2011 | 10:43 PM - Posted by Anonymous (not verified)

I have a dedicated mining machine which runs 24/7 in the closet (no, really -- it sits in the closet). It has the cheapest AMD CPU I could find (sempron processor), 1GB of ram, a flash drive used as the hard drive running Ubuntu 10.4 on a headless (monitorless) system. The only thing really going on is the 2x5850 Xtreme graphics cards pumping out ~ 700 MHash. When I bought this rig, it ran me $530 after rebates from Tiger Direct.

July 13, 2011 | 10:45 PM - Posted by Anonymous (not verified)

Linux or Windows doesn't matter. Windows will require a dummy plug on any secondary video cards because the OS won't see it unless it has a monitor plugged in.

July 13, 2011 | 07:18 PM - Posted by Allan (not verified)

I did an analysis of the energy costs, which really should be factored in: http://hardware.slashdot.org/comments.pl?sid=2321814&cid=36755990

July 13, 2011 | 08:35 PM - Posted by Ryan Shrout

We did that today as well!

http://www.pcper.com/reviews/Graphics-Cards/Bitcoin-Mining-Update-Power-...

July 13, 2011 | 07:27 PM - Posted by Anonymous (not verified)

The 5770 is also a pretty glaring lack, because it is the one that would compete the most with the 5830. It is definitely not as good, but it is definitely far easier to obtain a 5770 then a 5830.

July 13, 2011 | 08:36 PM - Posted by Ryan Shrout

Good point - we should try to add it this week.

July 13, 2011 | 10:47 PM - Posted by Anonymous (not verified)

5830s are not really hard to find in stock. I get 219 MHash from my 2x5770s -- Pretty far below (80ish?) what a 5830 gets you and they're not that much cheaper.

July 13, 2011 | 08:27 PM - Posted by Anonymous (not verified)

The way bitcoin distribute it fortune is a waste of our limited energy. Please stop it.

This is also not justly correct that only a few people get access to it and most people of the world is not having a chance

July 13, 2011 | 08:36 PM - Posted by Ryan Shrout

Obviously the hope is they spend it and put it back into circulation, right?

July 13, 2011 | 08:46 PM - Posted by Anonymous (not verified)

There is roughly about 8 megawatts being consumed. A diesel train engine generates 4 so the entire network consumes about the same as a train being pulled by two engines.

Whoop de do.

July 13, 2011 | 08:48 PM - Posted by Anonymous (not verified)

You can find complete mining and overclocking guides @ bitclockers.com

My GTX480 makes me 80 dollars a month right now.

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