Review Index:

Bitcoin Currency and GPU Mining Performance Comparison

Author: Ryan Shrout
Manufacturer: General

Testing Configuration and Software Setup

Software Configuration

True ease of use is something that the Bitcoin ecosystem doesn't really have yet though they are steadily improving on it.  You'll need a couple different items up and running on one or more machines to really start with your mining experience.

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The first thing you'll need is the Bitcoin client application that acts like your wallet and actually accesses your wallet.dat file.  While this doesn't necessarily need to be running on the same hardware that is doing the mining, you'll need to run this to get your key information to share with the mining apps. 

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For your mining application, there are several options including some command-line based apps and graphical ones.  For the quickest setup and configuration time we liked GUIMiner, seen above.  The interface you use does not necessarily determine the kernel you use for computing the Bitcoins and which kernel you use can alter performance pretty dramatically.  In its infancy the Bitcoin community ran CPU-based kernels until the performance difficulty got to a point where they were incredibly inefficient leading to the creation of several GPU-based designs.

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For our testing we went with the poclbm kernel that is built around OpenCL and works with AMD Radeon HD 4000 series and above and NVIDIA GeForce 8000 series and above graphics cards.  There definitely are other options out there for Bitcoin mining and many enthusiasts argue that some perform better than others across different ranges of CPUs and GPUs but in terms of popularity today, poclbm seems to be the winner.  

The above image shows us actually running a pair of the kernels, one for each GPU on a multi-GPU graphics card.  If you have more than one GPU in your system, whether on a single card or multiple, you need only assign a kernel to each available processor to max out your processing performance.  

(Side note: because it is built on OpenCL, you can actually run this on CPUs that have compliant OpenCL stacks.  However, it is not the most efficient on that class of processor by any means.)

When running a Bitcoin mining application be prepared for a lot of GPU utilization but not much on the CPU side of things.  

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Here you can see our Core i7 Sandy Bridge based processor is not getting a heavy workout while running the GUIMiner application with our OpenCL-based client focused on the GPU.  Looking at the graphics card workload however...

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The ASUS ARES card (dual Radeon HD 5870 GPUs) is working hard with a 99% GPU load reached and temperature slowly rising.  If you have a GPU with a loud fan or are sensitive to the heat created by your graphics card then this mining process might not be for you!

Hardware Configurations

For our testing we ran the Bitcoin clients on our standard GPU testing bed built out of the following:

  • Testing Configuration
  • ASUS P6X58D Premium Motherboard
  • Intel Core i7-965 @ 3.33 GHz Processor
  • 3 x 2GB Corsair DDR3-1333 MHz Memory
  • Western Digital VelociRaptor 600GB HDD
  • Corsair Professional Series 1200w PSU
  • NVIDIA Driver: 275.33
  • AMD Driver: 11.6

Our graphics card selection was based on trying to compare some current options to some previous generation cards that are likely to already be in the hands of potential GPU Bitcoin Miners.  Here is the lineup with a few curveballs tossed in:

  • GeForce GTX 285 - $300
  • GeForce GTX 295 - $289
  • GeForce GTX 460 - $160
  • GeForce GTX 560 Ti - $319
  • GeForce GTX 580 - $469
  • GeForce GTX 590 - $749
  • Radeon HD 4890 - $240
  • Radeon HD 5750 - $115
  • Radeon HD 5830 - $129
  • Radeon HD 5970 - $620
  • Radeon HD 6850 - $159
  • Radeon HD 6990 - $750
  • Radeon HD 5870 x2 (ASUS ARES) - $1100
  • Radeon HD 5870 x2 (Overclocked) - $1100
  • AMD A8-3850 APU - $139
  • "The Beast" - $1710

We have covered the bases of the last several years by starting with the HD 4890 and GTX 285 cards of yester-year.  We included a range of modern cards including the very popular GeForce GTX 460 and the lower end Radeon HD 5750.  Dual-GPU cards make a frequent showing with the GT X 295, GTX 590, HDF 5970 and HD 6990 as well as the ASUS ARES in a standard and overclocked setting.  Standard clock rate on the ASUS ARES is 850 MHz and our overclocked setting pushed that to 1005 MHz - an 18% increase. Basically, we just wanted to see how high we could push that $1100 graphics card.

The big outlier is the new AMD A8-3850 APU released this month that combines a quad-core CPU and "discrete class" GPU on a processor.  The Radeon HD 6550D GPU on that die (as it is branded) has 400 stream processors and uses a DDR3 memory interface that is shared with the x86 cores.  Because the computing process at work in Bitcoin mining is not memory dependent, we kind of expected the APU to do well for its price and position.  

The pricing listed here is used throughout our performance review to judge value and profitability.  Keep in mind that some of these numbers were hard to really nail down especially for cards like the GTX 285, GTX 295, HD 4890, HD 5970 and ASUS ARES that are hard to find anywhere but eBay and very small online stores.  The prices here are my best estimates at what you would have to pay (on average) to acquire a card like this today.

You might also be wondering what "The Beast" is in our list above.  That is a mega-crunching machine we put together after doing all of our other card testing to see just how much we could push out of a single system.  Using the same base test bed, we installed the Radeon HD 6990 4GB, Radeon HD 5970 2GB (both dual-GPU cards) and the Radeon HD 6970 2GB single-GPU cards.  While we wanted to include the ASUS ARES in this configuration we weren't given that option since it required three PCIe power connections and our Corsair AX1200 power supply only supplied us with six of them.  You will have to wait until later in the article to see the results of that setup as I decided to leave it off the single card result graphs as it tended to skew the scale quite a bit.

What to look for

The first thing you are going to notice is that the AMD graphics cards solidly outperform the NVIDIA GPUs for reasons we are still diving into.  The VLIW architecture at work on the 4000/5000/6000 series of cards is seeing some very high utilization by the poclbm kernel and it is definitely one of those few applications nearly reaching the theoretical limits of TFLOPs claimed by AMD over the years.  

What else is there to evaluate?

  • Pure Mhash/s rates - how fast is each GPU in computing the math required for Bitcoin mining?  The higher the Mhash/s rate the faster the card and quicker you will get to finding the next coin in the currency.
  • Performance per Dollar - Mhash/s/$ - This is probably the most important factor for users that might consider Bitcoin mining as a way to make money and pay for things they want to buy.  Which card is going to bring the most "value" the mining experience?
  • Performance per Watt - Mhash/s/watt - If you value your air conditioning bill more than most or maybe want to cram as many cards into an enclosure as possible for a mining power house you might want to know which cards and GPUs are the most power efficient.
  • Dollars per day - Step 1: Mine.  Step 2: ??  Step 3: Profit.  How much money can you make on a given card on a daily basis?  This metric will fluctuate from day to day based on the actual exchange rate of a Bitcoin with USD (or your own currency) but we will evaluate it based on the numbers as of this writing.
  • Time to Graphics Card Payoff - Based on the amount of money you can earn per day, how long will it take you to pay off the card you purchased for this purpose and start making the aforementioned profits?  Obviously for cards that are either end-of-lifed or just plain hard to find this is going to be a rough estimate (go ahead and find me an average price for a GTX 285 today) but it provides another useful data point for professional miners.
  • One Year Profit - If you took that daily earned amount and could apply it perfect for one year (which we know you can't really because of the changing algorithm) and subtracted the cost of that graphics card, how much could you possibly MAKE in a year?  The numbers might surprise you!

So there you have it - let's jump into the results and see what our testing brought forth with more details and explanations along the way!

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 :

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:

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

We did that today as well!

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 @

My GTX480 makes me 80 dollars a month right now.

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