Archive for the ‘Tests and Reviews’ Category

The enterprise segment is constantly upgrading their hardware and this fuels the second hand market with interesting and very affordable yet pretty powerful hardware that can also be used for crypto mining. The latest wave of hardware getting replaced and available at a really affordable prices are the first generation of Intel 2011 E5 dual CPU Xeon workstations and servers. This means that you are able to easily acquire a very nicely priced second had server system with two 8-core processors such as Intel Xeon E5-2650 v1 getting 16 physical or 32 logical cores with Hyper Threading. The big question here however is if systems like that that may be acquired cheap are really worth using for crypto mining as they only come with a lot of CPU power, but no GPU capable of being used for mining as for server needs not much GPU power is required generally. We have picked up one such cheap systems off eBay with dual Xeon E5-2650 processors and put it through some benchmarks to gent a better idea on what to expect…

Currently it seems that the only worthwhile CPU-based algorithm to check is the CryptoNight and using the what seems to be the fastest CPU software available at the moment – the XMR-Stak CPU Miner for Monero (XMR). Running the XMR-Stak miner on all 32 logical cores has managed to get us an average hashrate of about 523 HS (hashes per second). The result may not seem that bad for CPU mining, considering that it is a bit slower than a single high-end GPU and the power used by the system is about 150 Watts, so again similar to a more recent higher-end GPU.

We need to run the numbers through an XMR mining calculator and doing just that on Cryptocompare shows that we are actually going to be mining with profit, but the profit isn’t going to be that much. With the current rate it would take a couple of years just to earn back what we have paid for the hardware itself. Not very interesting to CPU mine with such a system, but this is just at the moment, with some new and interesting developments for coins that are only CPU mineable appearing things might look very different… especially if you get a couple of these dual CPU systems to have handy. For the moment however you might want to check them out if you have some other computational needs than crypto mining as the price they can be acquired for is really attractive and again they are still pretty powerful as far as CPU performance goes.

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The Brave browser is an interesting relatively new project for an open-source web-browser being developed with user’s privacy, security and performance in mind as well as with some interesting ideas to actually award users of the browser as well as allowing users to support their favorite websites without having to watch annoying ads on them. We like the idea, especially considering that the rewards part is also based on Bitcoin for the payments, so Brave is also supporting crypto currencies. A couple of months ago we have tried the browser in an earlier stage and there were still a lot of things that needed work, so we gave it another try with the most recent version. We already tried the ad and tracking blocking functionality and it has worked well even before, but this time the focus was a more recent feature that is still in beta – the Brave Payments feature. If enabled (off by default) it allows users to donate Bitcoins to their favorite websites where they do spend a lot of time and enjoy the content they find. As already mentioned this is powered by BTC transactions, so you need to actually have some Bitcoins and be willing to donate them…

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If you want to try the Brave Payments beta feature you need to open up the Brave browser’s settings and go to the Payments tab, where you will find an off-on switch that would allow you to enable the feature. The basic control panel here allows you to select a monthly budget from a dropdown menu (5 USD to 20 USD) and see what amount in USD you currently have (deposited in Bitcoin). Once you enable the feature you will get a Bitcoin wallet address generated for you where you can deposit BTC that will be used to support your favorite websites.

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There are multiple ways to obtain Bitcoins available, but after you have a hold of some you need to send them to the BTC wallet address you get shown when you click on the Add funds button in the Brave Payments window. Bitcoin transactions do require 1 confirmation on the network before the USD balance becomes available in your account.

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When you start using the Brave browser you will see a list of websites ranked by the time you spent on them, in this list you can choose which sites you want to support using the Include switch (it is ON by default, though it should probably be OFF for new ones). The monthly budget you set, provided that you have available balance in your Brave BTC wallet is going to be distributed each month to all of the websites you decide to support, getting split according to a percentages based on a combination of how many pages you visit and how much time you spend on each site. Payments from users to website publishers are being made once a month.

Site owners that want to be able to receive funds from users supporting them through the Brave browser will need to verify themselves. According to the information available that will happen once there are at least $10 USD in BTC available for them from users with confirmation/registration emails being sent to the domain owners and the webmaster of the website. We are yet to go through that procedure to see how it goes, but the rest we have tried does seem to work pretty well already.

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The Advanced Settings menu allows you to do some important things such as the minimum page time before logging a visit as well as the minimum visits fro publisher relevancy. You will most likely want to increase these values from their default lows in order to filter out random websites that you visit just once for example. The other very important functionality in this menu is the ability for backing up and recovering your Brave BTC wallet, this is something that you would want to make sure you backup just in case as you will be holding some amount of BTC in it if you will be using the Brave Payments feature.

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For the moment the only way to take advantage of the Brave Payments beta feature is if you deposit some coins in your Brave wallet, but in the future the Brave browser will allow you to also earn while suing the browser if you want to. The standard functionality of the Brave browser is to block ads, but it can also replace them with Brave ads and for seeing these both website publishers and users might also have an additional stream of income. Above is the table with the percentage share for profit that will be coming from replaced ads, 55% go to the publishers and 15% go to the people that actually see the ads using the Brave browser. For the moment however there are still no replacement ads available apparently, but in the near future we may actually see that functionality becoming available in beta as well, just like the Brave Payments feature now.

For more information and to try out the Brave browser and the Brave Payments feature…

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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.


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