Archive for the ‘Tests and Reviews’ Category

How to Choose the Best PSU for a Multi-GPU Mining Rig

21, Nov 2016

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It seems that still a lot of people may overlook the importance of the power supply when building a multi-GPU mining rig and the more the number of video cards, the more the issues may arise. Normally people think that if you have six video cards with a TDP of 150W, then any decent 1000W power supply should be just fine for the job in providing enough power for the mining rig. Doing the simple math it will, however when we get to actually connecting everything things may actually start to get messy. You might discover that you have not properly planned the number of power connectors you need for the video cards that you need, or the number of 4-pin Molex connectors needed for the powered risers. The simplest solution here would be to just add some splitter adapters and got a few extra connectors available to be able to just connect everything. Unfortunately the simplest solution here is definitely not the wisest thing to do as you might end up overloading some of the wires going to the PSU…

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The first thing you need to ensure is that the power supply you go for has enough PCI-E power connectors available to power all of your video cards in the mining rig. So if you have 6 video cards getting six separate PCI-E power connectors from the power supply is the best solution. Unfortunately not many power supplies are designed with single cables for 6 or even more PCI-E power cables as normal computers rarely have more than 2 or up to 4 video cards in rare cases. Even if a power supply has let us say 8 power connectors these are usually double connectors going from a single wire to the PSU and this is originally designed for up to 4 video cards (if they have double PCI-E power connectors). Adding additional adapters splitting single PCI-E power connector to dual PCI-E or using Molex to PCI-E power adapter can cause problems, so if possible it is wise to try and avoid it. If not, then you at least need to make sure that you are not overloading any of the lines going to the power supply, the easiest thing to check for that is to touch the cables and if they are getting hot, then it is not Ok.

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If you are using a motherboard with multiple PCI-E slots like the AsRock H81 Pro BTC motherboard that is actually designed to be sued for GPU mining rigs you will need to use extenders. Although the motherboard has extra 4-pin Molex power connectors in order to properly power video cards that need more power from the PCI-E slot. Even in this case it is still better to go for powered PCI-E risers and do not try to draw more power through the motherboard, especially if you go for 6 GPUs. The x16 PCI-E slot that is normally being used for video cards on the motherboard is designed to provide up to 75W of power to the video card by specifications, though most of the consumption comes from the 12V line and there the max power is rated at up to 66W. If you however have 6 video cards that are maxing out the power draw from the motherboard it will come up to a pretty high number, even though in most cases video cards do not go with the maximum power that the PCI-E slot can provide them with.

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There are a number of different PCI-E risers, but one that is very popular choice is the x1 PCI-E to USB 3.0 riser as it is really well designed and works very good, unlike the case with not so well made ribbon cable extenders. These risers use a USB 3.0 cable, but they are not actually using USB interface, the cable is just a good choice for the data communication without issues. PCI-E risers like the one on the photo rely on 4-pin Molex power connector to supply any power that the video card may need, completely cutting any power draw from the motherboard’s PCI-E slot. We already know that the video card can draw up to 66W over the 12V line and this should normally not be a problem for a 4-pin Molex connector as these connectors are rated at 10-11A per wire and since there is just one 12V wire you should in theory be able to go for up to 120-132W over it, but that is only if you have a single Molex power connector.

The actual problem with 4-pin Molex power connectors are not the connectors themselves, but the cables that are being used to route them to the PSU, because they also have a maximum power rating depending on their thickness. Power supply manufacturers and cable adapter manufacturers do not go for the best option as it would make things more expensive and in most cases it will not hurt to go for a thinner cable. To be able to get up to 10A current over a 4-pin Molex connector you would require a 14 AWG or 16 AWG wire, 18 AWG ones are rated at up to 8 Amps and 22 AWG wires are rated for up to 6 Amps. Unfortunately most manufacturers do not go for 16 AWG let alone for 14 AWG wires on Molex connectors (usually 16 AWG wires used on PCI-E power connectors on high-end power supplies). In most cases the power supply wires for the 4-pin Molex connectors are 18 AWG, though there are cases, especially for adapters or extenders where even cheaper 22 AWG wires are being used.

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If the maximum power draw for a video card over the 12V line of a PCI-E slot is 5.5A (66W) then even a 22 AWG wire rated at 6 Amps should be enough. It should, but only if you connect only one such 4-pin Molex power connector to a line going to the power supply. That is rarely the case however as power supplies normally have a couple such 4-pin Molex connectors on single line going to the power supply and that goes over a 18 AWG wires. In order to be safe a maximum two PCI-E extenders should be powered by such cables to stay within specs or at least close to them, but people often use three or even four of these connected and that can lead to cables overheating and melting or even burning and damaging your expensive mining hardware as a result.

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Normally with video cards that have external PCI-E power connector the maximum of 66W over the PCI-E slot is never reached, it will be more like up to 30-40W for example (or less), though there are exceptions as well – the reference design Radeon RX 480 GPUs. Even at 40W if you connect three or four of the 4-pin Molex power connectors that use a single cable line to the power supply, then you will still be over the maximum rating of the cables. What happens is the cables starting to heat up and as a result they may even melt and short out and that can do things like start a fire, damage your video cards, motherboard or power supply etc.

The easiest way to discover such a problem is to just touch the power cables a few minutes after you have the mining rig up and mining, so that it is under heavy load and using a lot of power. Cables that are hotter to the touch than the others are probably near or over their limit and you should think of a way to reduce the power draw over the specific power line to the PSU. If you have a thermal camera you can just take an image like the one above and see the problem clearly and diagnose which cable might be overloaded and do something about it. But even if you don’t have extra tools to assist you, even just touching and noticing a hotter cable can be enough to find an issue with the power distribution of your mining rig. Do not overlook possible issues like that as later on they may cause you serious headaches and even cost you a significant amount of money, taking you on the red, instead of you actually making profit from mining.

Crypto Mining Performance of the Nvidia GeForce GTX 1050 Ti

25, Oct 2016

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A couple of days ago Nvidia has introduced their new lineup of GTX 1050 and GTX 1050 Ti GPUs, entry level for gamers and the successor of the popular GTX 750 Ti and the more recent GTX 950. We got an MSI GeForce GTX 1050 Ti 4G OC video card to give it a quick test and see what Nvidia has to offer with their new GPUs in terms of performance in some of the most popular crypto mining algorithms. While the GTX 1050 Ti may not be the most powerful solution for mining, the interesting part here is the lower power consumption per board just like it was back when GTX 750 Ti was released. So while it may not be the best choice for more serious multi-GPU mining operations, it could still be a viable option for a lower power home mining rig with 6x GTX 1050 Ti for example.

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The GeForce GTX 1050 and GTX 1050 Ti are originally intended to be used without external power and have a TDP limit of 75W (because of the PCI-E slot), though we expect that there will be some companies offering more serious models with external PCI-E power. Do note that if you plan on building 6x GTX 1050 Ti GPUs mining rig you will still need to use powered extenders in order to avoid the possibilty of damaging the motherboard as the power draw from these will be significant.

When we consider the fact that the new GPUs are based on 14nm production process (the first GPUs to go down from 16nm to 14nm for Nvidia) and apparently do have some nice headroom for overclocking. We have managed to get +195 MHz on the core and +150 MHz on the video memory with the default voltages and what was limiting us from going further was the power limiter as the card was hitting the TDP and could not boost the operating frequency that much. Still the maximum frequency of the GPU it managed to hit briefly was 1911 MHz, so with higher power limit and with better cooling such operating frequencies might be available for constant boost.

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Here are the numbers, comparing the performance of GTX 750 Ti, GTX 950 and GTX 1050 Ti using the latest NiceHash Miner software to get the hashrates of various popular GPU mining algorithms at the moment. As you can see there is a really nice improvement in hashrate between GTX 750 Ti and GTX 1050 Ti, maybe with some decent overclock the new GPU could even get to double the performance in some algorithms. Nevertheless the improvement from GTX 750 Ti is good in terms of performance and while there is also decent improvement from what GTX 950 offers, it is not that significant really. The main reason for that is the fact that specifications wise the GTX 950 and GTX 1050 Ti look pretty similar, even though they are based on different architectures it is much like the older one is just a bit slowly clocked and has somewhat higher power usage. Still the GTX 950 is pretty much in between the GTX 750 Ti and GTX 1050 Ti in terms of hashrate in pretty much all algorithms apart from Cryptonight where the weird result is most likely due to the lack of optimizations.

In the end the new Nvidia GeForce GTX 1050 Ti is really a good improvement over the GTX 750 Ti in terms of mining performance, you could probably get the a bit higher mining performance from 4x GTX 1050 Ti as with 6x GTX 750 Ti, and the power usage will be lower. You could still build a good mining rig with decent hashrate using 6x GTX 1050 Ti GPUs and do with a 600W power supply just fine. Of course, as already mentioned it might not be the best choice for serious mining operations where GTX 1070 would perform much better in terms of performance, but for home miners it could still be a viable option… just like GTX 750 Ti did when it first came out.

– More on the technical specifications and the differences between the GTX 1050 and GTX 1050 Ti..

First Impressions from the Baikal Mini Miner ASIC

14, Sep 2016

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We have been playing around and testing the Baikal Mini Miner for a few days now and we are ready to share our first impressions from the device. First off it really works and works well with all of the six supported algorithms – X11, X13, X14, X15, Quark and Qubit. This is the first and only ASIC manufacturer (to our knowledge) to offer a dedicated ASIC miner supporting multiple algorithms (though they are not that different from each other). The device is able to deliver the promised hashrate of about 150 MHS in the different supported algorithms and does it with a low power usage also as promised in the specs. Furthermore thanks to the low power consumption is it really compact and nowhere near as noisy as we are used to get from ASIC miners lately, so the Baikal Mini Miner is actually great for a home crypto currency miner.

We are going to be talking more about exact numbers as well as technical details in a future post about the Baikal Mini Miner. This post covers our initial impressions from the device after a few days of normal mining usage to confirm it is working stable and reliable and it does indeed do that. The build quality and the overall design is probably not the best out there, but it works well and apparently allows for easy stacking up of multiple devices as we’ve seen form the Baikal Quadruple Miner that essentially stacks for of these devices together. Everything about the device looks pretty impressive so far aside from the price, the device is being sold for about $500 USD or 56 DASH coins. So it seems a bit expensive, but it is not when you compare it to the competition in terms of X11 ASIC miners that are less power efficient for the hashrate they provide and end up costing you more for the same hashrate. Not to mention that they only support X11, while this one comes with support for 5 other algorithms, so it is more usable and offers support for significantly more crypto coins.

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The Baikal Mini Miner comes with its own mini computer unit similar to a Raspberry Pi that essentially controls the device, so there is no need to actually connect it to a computer for it to work. All you have to do is connect it to your Ethernet LAN network and then open up the web interface for control and monitoring of the device through a browser, the device uses DHCP to get an IP address on your network. The web interface is a modified version of Scripta mining distribution for Raspberry Pi. The default password for the web-interface is baikal and the username and password for the console login are also the same baikal and baikal respectively. You should be able to change them for security reasons of course, though be careful when you change them to note the new passwords for access.

The Scripta mining distribution works stable and really well with the Baikal Miner, it is easy to configure and monitor the device with it. There is a temperature sensor available and it is being reported by the software, though you probably will not be interested much in it as the temperature of the miner is really low. The switching between the 6 supported mining algorithms is as easy as clicking a button after you configure mining pools for each of them of course. The software supports priority based failsafe switching between pools/algorithms. What it could really use however is some sort of automation for profitability based switching between the supported mining algorithms.

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Talking about profitability we cannot forget to do some calculation on the actual profitability of using the device as this is the factor that can be decisive in you choosing to get it or not. The Baikal Mini Miner does come with support for 6 mining algorithms, though not of them are really that popular and widely used. For example X11 is quite widespread, but there are already a lot of X11 ASIC miners on the market, yet it is still often the most profitable one to mine. Other such as X14 and X15 were never that popular, so unless there are some new coins coming out using them there are probably not that much worth mining (they use more power). Mining Quark and Qubit can also do you some good profit if you manage to catch something good. So for actual profit you will probably have to go looking for new coins or for trending ones and risk a bit more and mine them.

If you decide to go the safer way and just sell your hashrate on a service such as NiceHashfor example you will have a bit more stable and reliable profit in Bitcoin, but it might not be as high as if you can get by mining the right coins at the right time. Based on our experience using NiceHash with the Baikal Mini Miner we can say that you can expect to get something like 0.0034 BTC per day with the more profitable algorithms. That is like $2.08 USD a day, fortunately the power used by the device is really very little and the cost is not much, something like up to 1 kWh per day. So making let us say $2 USD per day and $60 USD per month it would take you more than 8 months to get enough to cover the cost of the miner. Not that much, but not that little time for the crypto currency world either, and that is only if the current conditions remain for the duration of the next 8 months. Of course you can also risk it and try to get more profit than using the more safer way, though in the end the result might be either better or worse. It is up to you to decide…


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