Having launched its fastest graphics card to date on Tuesday, AMD will find few takers among scrypt miners, argues Nermin Hajdarbegovic.



AMD’s new card is pricey and designed with enthusiasts in mind, so few miners will be willing to pay the premium for an elaborate hybrid cooler. What’s more, an increasing number of scrypt miners are looking beyond Radeon graphics processing units (GPUs) for their mining needs.

With that in mind, the dual-GPU Radeon R9 295X2 is starting to sound like a swan song for GPU mining, at least as far as scrypt goes.

Meet the R9 295X2, AMD’s new flagship

The Radeon R9 295X2 is the latest card in a long line of dual-GPU graphics cards from AMD. It is based on the 6.2bn transistor Hawaii XT GPU, the same chip used in the R9 290X. Each GPU packs 2816 stream processors, 176 texture units and 64 ROPs. The GPUs are paired with 4GB of GDDR5 on a 512-bit bus. In essence it’s like having two R9 290X cards on a single printed circuit board.

The closed loop hybrid air/water cooler helps the card maintain high boost clocks, which was not the case with the reference R9 290X design, which quickly ran up against the thermal barrier in AMD’s Uber mode. AMD says the R9 295X2 can consume up to 500W. The suggested retail price is $1,499, or €1,100 plus VAT in Europe.

The price makes it more or less pointless for GPU miners, as they would much rather invest in two R9 290X cards, with a suggested retail price of $549. However, buying an R9 290X at that price has been next to impossible for months due to strong demand. This appears to be changing.

Miners are saving their cash for scrypt ASICs

AMD has been struggling to meet demand for Hawaii-based cards for months. The R9 290X was on allocation for a while and the shortage also led to plenty of price gouging, especially in Europe and North America.

Contrary to many reports, the shortages were not caused solely by miners, although they contributed to them. AMD’s Hawaii cards tend to offer good value for money compared to Nvidia’s high-end cards and AMD sweetened the deal with Mantle, a proprietary API that enables developers a “close to metal” approach and eliminates plenty of CPU overhead. The Mantle API still lacks support, but there are plenty of studios that have already signed up, making the cards a bit more appealing.

Demand for Radeon R290-series cards has dropped over the past few weeks. Miners have been scooping up Hawaii-based and Tahiti-based Radeon cards by the dozen for the past few months. However, retailers and distributors say demand is finally cooling down. It appears that miners are waiting for more scrypt ASICs, which is understandable.

It should be noted that this only applies to scrypt. There is always a chance that someone out there will come up with a popular altcoin based on a new ASIC-proof algorithm, but don’t hold your breath. There is already plenty of altcoin fatigue.

Performance-per-watt conundrum

Radeons still account for much of the computing power behind scrypt altcoins such as litecoin and dogecoin. However, they are no longer the money making machines they once were. Difficulty is going up and the first ASICs capable of handling scrypt are rolling out.

One example is the GridSeed ASIC hybrid miner, which can mine both scrypt and SHA cryptocurrencies. GridSeed offers a range of miners ranging from $205 to $27,195.

For example, GridSeed’s Set B – 5X 2M package features five 55nm ASICs capable of churning out 330-450KH/s at 4-7W. It is priced at $1,375, so it costs about as much as a pair of Radeon R9 290X cards and it’s roughly on par in terms of performance, as the R9 290X delivers about 1MH/s. However, the Radeons consume up to 250W each, but in reality the number can go up to 300W under load, especially if some overclocking is involved.

On top of that you’ll need a motherboard, power supply unit, CPU and a few other components to build a GPU mining rig, which basically means you will end up spending more to get inferior performance-per-watt.

As if that isn’t bad enough, comparing Radeons to upcoming scrypt miners paints an even bleaker picture for GPU mining. KnCMiner recently updated the spec for its upcoming Titan miner, which will now deliver up to 250MH/s and will require a standard 800W-1000W power supply unit. To get that sort of performance out of Radeon-based rigs a miner would need about 250 cards rated at 250W each, not including the consumption of other components.

Possible RMA fallout

GPUs still have one advantage on their side. Miners can use them for weeks or months and then simply sell them as used graphics cards. Selling used ASICs is a lot harder, especially in small markets. While miners would probably find a lot of interest for used ASICs in places like the US, Germany or China, in many smaller countries they would have to look abroad, with all the bureaucratic mess that entails. Unloading unneeded GPUs is a lot easier and depreciation tends to be much lower.

However, there is a problem. Many miner cards have a lot of mileage on them. Bear in mind that these are consumer products, and were not designed to run under full load for months at a time. The average gamer does not push the graphics card to its limits more than a few hours a day. These are the numbers AMD takes into account when it works out its return merchandise authorization (RMA) scenarios. Some cards are always expected to die an untimely death, so AMD and its add-in-board partners are usually willing to replace them free of charge.

However, they can refuse to do so if the cards were abused.

This may be a problem for some miners. Serious miners with dozens of cards tend to buy the cheapest available cards, namely reference cards with stock coolers rather than overclocked cards with non-reference coolers. In many cases the cards will be underclocked rather than overclocked, trading performance for efficiency. There are exceptions though – some miners overclock their cards.

A card that has spent six months mining for altcoins has more than 4,300 hours on it, under full load. The same card in a gaming rig, with two hours of load per day for six months, had to deal with just 360 hours of full load, if that. Games don’t push cards to 100% load all the time, so two hours of full load is usually what gamers get from extended gaming sessions. All the load takes its toll on various components, ranging from voltage regulator modules to fans and GPUs themselves.

In other words, people who know what they are doing will avoid mining cards in the second-hand market, so they may not be as easy to unload as some miners expect. Selling a couple of cards shouldn’t be hard, but selling dozens at once will, as many gamers will stay away from them to avoid possible RMA issues.

Nermin Hajdarbegovic is a freelance opinion and news writer for CoinDesk: his opinions do not necessarily reflect those of CoinDesk.