If you typically follow GPU performance as it related to gaming but have become curious about Bitcoin mining, you’ve probably noticed and been surprised by the fact that AMD GPUs are the uncontested performance leaders in the market.This is in stark contrast to the PC graphics business, where AMD’s HD 7000 series has been playing a defensive game against Nvidia’s GK104 / GeForce 600 family of products.In Bitcoin mining, the situation is almost completely reversed — the Radeon 7970 is capable of 550MHash/second, while the GTX 680 is roughly 1/5 as fast.There’s an article at the Bitcoin Wiki that attempts to explain the difference, but the original piece was written in 2010-2011 and hasn’t been updated since.It refers to Fermi and AMD’s VLIW architectures and implies that AMD’s better performance is due to having far more shader cores than the equivalent Nvidia cards.This isn’t quite accurate, and it doesn’t explain why the GTX 680 is actually slower than the GTX 580 at BTC mining, despite having far more cores.

This article is going to explain the difference, address whether or not better CUDA miners would dramatically shift the performance delta between AMD and Nvidia, and touch on whether or not Nvidia’s GPGPU performance is generally comparable to AMD’s these days.Topics not discussed here include:These are important questions, but they’re not the focus of this article.We will discuss power efficiency and Mhash/watt to an extent, because these factors have an impact on comparing the mining performance of AMD vs.Nvidia.Bitcoin mining is a specific implementation of the SHA2-256 algorithm.One of the reasons AMD cards excel at mining is because the company’s GPU’s have a number of features that enhance their integer performance.This is actually something of an oddity; GPU workloads have historically been floating-point heavy because textures are stored in half (FP16) or full (FP32) precision.The issue is made more confusing by the fact that when Nvidia started pushing CUDA, it emphasized password cracking as a major strength of its cards.

It’s true that GeForce GPUs, starting with G80, offered significantly higher cryptographic performance than CPUs — but AMD’s hardware now blows Nvidia’s out of the water.The first reason AMD cards outperform their Nvidia counterparts in BTC mining (and the current Bitcoin entry does cover this) is because the SHA-256 algorithm utilizes a 32-bit integer right rotate operation.bitcoin bursaThis means that the integer value is shifted (explanation here), but the missing bits are then re-attached to the value.bitcoin visual studio 2010In a right rotation, bits that fall off the right are reattached at the left.bitcoin calculator hashAMD GPUs can do this operation in a single step.bitcoin boxing betting

Prior to the  launch of the GTX Titan, Nvidia GPUs required three steps — two shifts and an add.We say “prior to Titan,” because one of the features Nvidia introduced with Compute Capability 3.5 (only supported on the GTX Titan and the Tesla K20/K20X) is a funnel shifter.litecoin calculator exchangeThe funnel shifter can combine operations, shrinking the 3-cycle penalty Nvidia significantly.bitcoin price rise graphWe’ll look at how much performance improves momentarily, because this isn’t GK110’s only improvement over GK104.GK110 is also capable of up to 64 32-bit integer shifts per SMX (Titan has 14 SMX’s).GK104, in contrast, could only handle 32 integer shifts per SMX, and had just eight SMX blocks.We’ve highlighted the 32-bit integer shift capability difference between CC 3.0 and CC 3.5.AMD plays things close to the chest when it comes to Graphics Core Next’s (GCN) 32-bit integer capabilities, but the company has confirmed that GCN executes INT32 code at the same rate as double-precision floating point.

This implies a theoretical peak int32 dispatch rate of 64 per clock per CU — double GK104’s base rate.AMD’s other advantage, however, is the sheer number of Compute Units (CUs) that make up one GPU.The Titan, as we’ve said, has 14 SMX’s, compared to the HD 7970’s 32 CU’s.Compute Unit / SMX’s may be far more important than the total number of cores in these contexts.Next page: Wrath of the Titan…Product Round-up Bitcoins are either the new bubble economy or the future of online commerce.It’s not the first time anonymous e-money has been tried – ask Mondex – but Bitcoin does seem to have traction.There are things you might want that you can buy with it, such as Tesla cars and Virgin Galactic trips to space.Zynga has announced that it will take Bitcoin for in-game payments, and there is a host of things you can buy through Bit Premier.So, if you want to get into mining - perhaps you have some rack space doing nothing - you need to know what is on the market.This is an ambitious article.

It aims to tell you what is available and what it costs.In any other market that’s reasonable, but here products go in and out of stock constantly, driven by an erratic supply chain, particularly for chips.Prices reflect the value of Bitcoins, prices of rival hardware and the availability of that rival hardware.And much of this is shrouded in truths, half-truths and lies.Even more secretive is the company 21e6 which has raised $5m to build ASICs it will only use itself.Comparing the miners starts with understanding what it takes to make a Bitcoin.Please forgive any over-simplification.Briefly, there is an algorithm to work out what is the next Bitcoin to be mined.Solving this requires a number of hashing operations.How many depends on how many coins have been minded previously so it’s an increasing level of difficulty.Initially this could be done with moderately specced PC but as more coins got mined this moved to using code, which took advantage of the super-fast graphics processors on video cards and then to dedicated hardware: ASICs designed purely to mine Bitcoins.

Even these have evolved from homebrew to large technical teams.If the bottom falls out of the Bitcoin market, all that equipment is useless.There is no other purpose to which it can be put.The processing is immense.While you can’t directly link mining hashes with FLOPS, it has been a couple of months since Bitcoin mining passed 1019 petaflops, or roughly the computing power of all the other computing tasks in the word - not allowing for what might go on in the NSA and GCHQ.Which is where this round-up comes in.What hardware should you buy?How much money will it make and how easy is it to run?How lucrative the process is depends not only on the cost of the hardware but the time you have to tend it, how stable it is and, crucially, how many hashes it can do for a given time and the cost of the electricity to do this.The value of coins often drops below the cost of the electricity used to make them.Although this of course depends on what you pay for your hosting.Data centres in places with cheap electricity, notably geothermally rich Iceland can become very attractive.

The costs need to be balanced against the increasing global difficulty of creating a coin against all the other people who are doing the same thing.It’s an arms race of processor design against the rising difficulty.Newer, faster processors are more expensive but stand a better chance of producing Bitcoins against the rising difficulty, and are more power efficient.Power consumption is generally rated in Watts (W) rather than KW/h and processing in hashes per second, expresses as Gigahash (GH/s), Terrahash (TH/s) and even Petahash (PH/s), especially when looking at global figures.There is are a number of calculators to help.A further level of complication is that the value of what you are producing is incredibly variable.Bitcoin value in terms of hard currencies are wont to fluctuate by 10 per cent or more a day.On 4 December, one coin was worth over $1,100, two days later it was under $700 and two days after that back at $900.You can see values double and halve almost weekly.Some hardware is bought in Bitcoins but there has been a trend to dollar pricing, even from European vendors.

This round up is a guide, a good starting point.You should be wary of a plethora of sites which are selling Bitcoin mining hardware and which don’t have a buzz about the products on the Bitcointalk forum.The business is full of scammers.In general the nastier the website the more likely the manufacturer is to be kosher.Those who are busy designing ASICs just knock up something in Wordpress.Scammers are much more likely to have time for finely crafted HTML 5.AsicMiner is not the only company to both sell and use the hardware it has designed and built, but it still makes for an uncomfortable relationship with customers given the rapidly increasing difficulty of mining Bitcoins.A couple of days soak test before shipping can radically affect the profitability of the equipment.The company crowdfunded itself not using Indegogo or Kickstarter but through Bitcoin fora.AsicMiner’s own mining operation, Allied Control, uses immersion cooling: it dips the boards into a very advanced 3M Novec liquid which boils at a low temperature to use the state change to absorb the heat very efficiently.

This points the way for data centres, particularly those mining Bitcoins.The initial product was a card containing 32 hashing chips and which plugged into an HP backplane.This has been superseded by the Cube, which uses the same 130nm ASICs but on four, smaller cards.Despite it’s finished appearance, the Cube needs quite a bit of work to get it going.It does not have a PSU built in: it’ll need one of at least 200W per card, more if you plan to overclock.Think around a kilowatt.At the standard speed it’ll produce 30GH/s.Ramp up the power and you might get 38.To get it running you need to log into an incredibly crude on-board web server and configure it.This is non-trivial and involves writing a script to start the mining.It’s a shame that something which looks so plug-and-play needs so much tending.A web page which asked you which mining pool you wanted to join, what your wallet was and what speed you wanted to run at, would make it so much more attractive.However, AsicMiner seems to sell all the kit it makes and is one of the few companies with a solid history of shipping products, so perhaps it has no need to finesse the Cube.

Avalon was one of the first companies to make a Bitcoin mining ASIC, despite not announcing the chip until after its rivals had announced theirs.It was for a time the dominant chip vendor.It sold the ASIC with Batch 1 and then Batch 2 hardware; there were rumours of Batch 3 hardware.People who had ordered one but didn’t receive hardware eventually got refunds, in Bitcoins – so at least they didn’t lose out on the appreciating value of the Bitcoins they had used to order the equipment.It’s widely believed that Avalon used the equipment to mine Bitcoins for themselves rather than shipping kit to punters.Avalon Clones sells ready-to-go systems based on Avalon’s Batch 1 machine.They come with a PSU, a one-year warranty on the board and a web interface, but the year-old 110nm processors are so far behind the curve today that a $20,000 machine is out-performed by newer $2,000 ones.“Delivery may take two months or more after order,” the company warns.This is a dedicated processing card fitted with 16 Bitfury ASICs and manufactured by the Belgian company CryptX.

The design, by the German company Burnin’ Electronics, is reported to be the best using the 55nm Bitfury chips.It’s the rig I know best as I’ve been running a two-card set-up since early December.The kit includes the cards and spacer legs to form a tower.A supplied fan attaches to the edge of a heatsink which covers all the ASICs.You have to add power and control.I used a 500W PC power supply and fooled it into thinking it was connected with a paperclip.For control I used a Raspberry Pi and the cgminer software.This talks to the mining pool over an Ethernet connection and to the Bitburner via USB.One of my boards had a bunged up USB port which made re-flashing it very difficult, and forums are full of comments of similar problems.This hardware was assembled in a hurry.All control is by command line, so being comfortable with a Linux prompt is a bonus in the Bitcoin learning curve.In use, cooling is everything.I found that the single fan over two cards was not enough to keep the temperature below the 60°C at which it stops working unless I sat it on a window shelf and opened the window a crack.

With a second fan and the window still open I could crank up the overclocking to get around 100GH/s combined from the two cards.Not allowing for the heat loss to the room the electricity cost works out at around 2p/hour.The cards cost around £1500, although they were bought in Euros.It then gets a bit man-maths.Over the month of December as the network difficult grew, the rig dropped from producing one bit coin every ten days to one every 25 days.Given a Bitcoin value of, say, £500 which is as good a number as any, it should pay for itself in six to eight weeks.It will have to run slower in the summer.Bejing-based Bitmain Tech does all it can to look suspicious: it’s bad at answering personal mails through the forums and primarily communicates through Twitter.It does have a website now.Products have, however, shipped and they seem kosher.One customer even posted a video.The AntMiner S1 is the firm’s first product based on its own BM1380 processor, a 12mm² 55nm device with eight cores.