As we have talked about on several different occasions, Altcoin mining (anything that is NOT Bitcoin specifically) is a force on the current GPU market whether we like it or not. Traditionally, Miners have only bought AMD-based GPUs, due to the performance advantage when compared to their NVIDIA competition. However, with continued development of the cudaMiner application over the past few months, NVIDIA cards have been gaining performance in Scrypt mining.
The biggest performance change we've seen yet has come with a new version of cudaMiner released yesterday. This new version (2014-02-18) brings initial support for the Maxwell architecture, which was just released yesterday in the GTX 750 and 750 Ti. With support for Maxwell, mining starts to become a more compelling option with this new NVIDIA GPU.
With the new version of cudaMiner on the reference version of the GTX 750 Ti, we were able to achieve a hashrate of 263 KH/s, impressive when you compare it to the performance of the previous generation, Kepler-based GTX 650 Ti, which tops out at about 150KH/s or so.
As you may know from our full GTX 750 Ti Review, the GM107 overclocks very well. We were able to push our sample to the highest offset configurable of +135 MHz, with an additional 500 MHz added to the memory frequency, and 31 mV bump to the voltage offset. All of this combined to a ~1200 MHz clockspeed while mining, and an additional 40 KH/s or so of performance, bringing us to just under 300KH/s with the 750 Ti.
As we compare the performance of the 750 Ti to AMD GPUs and previous generation NVIDIA GPUs, we start to see how impressive the performance of this card stacks up considering the $150 MSRP. For less than half the price of the GTX 770, and roughly the same price as a R7 260X, you can achieve the same performance.
When we look at power consumption based on the TDP of each card, this comparison only becomes more impressive. At 60W, there is no card that comes close to the performance of the 750 Ti when mining. This means you will spend less to run a 750 Ti than a R7 260X or GTX 770 for roughly the same hash rate.
Taking a look at the performance per dollar ratings of these graphics cards, we see the two top performers are the AMD R7 260X and our overclocked GTX 750 Ti.
However, when looking at the performance per watt differences of the field, the GTX 750 Ti looks more impressive. While most miners may think they don't care about power draw, it can help your bottom line. By being able to buy a smaller, less efficient power supply the payoff date for the hardware is moved up. This also bodes well for future Maxwell based graphics cards that we will likely see released later in 2014.
To illustrate this example, we put together two builds of mining computers that should be capable of similar hashrates:
|R9 270X Mining Rig||GTX 750 Ti Mining Rig|
|Processor||AMD Sempron 145 - $55||AMD Sempron 145 - $55|
|Motherboard||GIGABYTE GA-990FXA-UD3 - $135||GIGABYTE GA-990FXA-UD3 - $135|
|System Memory||Kingston Value RAM 4GB 1333MHz - $40||Kingston Value RAM 4GB 1333MHz - $40|
|PCIE Riser Cards||1 x 16X to 1X Converter - $10||3 x 16X to 1X Converter - $30|
|Power Supply||Corsair CX750 Builder Series - $80||Corsair CX500 Builder Series - $50|
|Graphics Cards||4 x Radeon R9 270X - $1200||6 x MSI Graphics Cards N750Ti - $990|
|Price||$1520 - Full Cart on Amazon.com||$1300 - Full Cart on Amazon.com|
In these two builds, the core platform stays the same, with the AMD Sempron 145 Single Core processor. While this processor would be essentially useless for a lot of other tasks, Coin mining on a GPU is not a CPU intensive task, so we can get away with one of the cheapest CPUs on the market.
We chose the Gigabyte 990FXA-UD3, as it was the cheapest motherboard we could find for this platform with 6 PCI-Express ports.
As you have probably noticed not all of the PCI-E ports on this motherboard allow for a x16 card to be plugged in, and even the ones that are capable don't have proper spacing for 2 slot cards. To remedy this we have included the appropriate adapters.
Due to the fact that we are using PCIE risers, there is no case included. You would most likely be best served by building an open-air test bed for the system out of milk crates, shelving systems, wood, or some other building material. Just remember, it doesn't have to look pretty to be effective!
There is also no storage option included. For something like this you could either use any spare hard drive you have laying around, or even install a Linux distribution to a thumb drive. Due to this, we found storage to be a negligible option.
First, we have a more traditional build, using 4 x R9 270Xs, which we found available on Amazon right now for just above $300 each. With 4 of these cards running at about 450KH/s each, we should have a 1.8MH/s machine. With a power draw of 150W from each card, we get a total of 600W just for the GPUs alone. Throwing in another 75W for the 45W TDP processor and any additional overhead, we come to approximately 675W power draw for our entire mining rig.
At a total cost of around $1520, this machine would have a payoff period of about 113 days at the current Dogecoin rates, at 1.8MH/s
Our second build is based on the GTX 750 Ti. This time we instead opted for 6 x 750 Ti cards for a total of $900, which is still significantly lower than the $1200 for 4 270Xs. With 6 x 750 Ti cards, the estimated GPU power draw would only be 360W, just above half of the power draw of the 270X machine. Adding in the same 75W for additional system components the total estimated power draw works out to 435W, which allows us to purchase a cheaper power supply.
At a total cost of around $1300, this machine would have a payoff period of about 97 days at the current Dogecoin rates, at 1.8MH/s
As you can see, by cramming more of the lower end but impressive GTX 750 Ti's into a single machine you can create a similar performing machine for less money than the AMD alternative, which is contrary to all the advice given about coin mining up to this initial release of Maxwell. In addition, performance of the Maxwell-based machine should only improve as the Maxwell kernel for cudaMiner is developed further, whereas OpenCL performance for AMD mining has likely been as optimized as we will ever see it.
An additional factor you have to keep in mind is the fluctuating cryptocurrency market. Just because the payoff estimates today say you could be making a profit in 80 days, doesn't mean that will remain the same in the future. While the estimate could get better, it also could get a lot worse, leaving you with a lot of hardware to sell off in the future.
While no one is sure where the mining market will be as far as profitability is concerned when the high end Maxwell GPUs hit the market, NVIDIA could have a similar stock issues and an inability to deliver GPUs to gamers as we see AMD having today.