Free Bitcoin mining in the office: Antminer U3 review

Yesterday, I said in a QQ group that I was using Antminer U3 to mine. A senior person named Li Kuang said, "Old Fan, how did you fall to using U3 to mine?" I think the word "fall" is a poor word. It should be "rising"! It is already June 2015. The Bitcoin market is as bad as shit. Mining has reached a bleak situation where you have to pay 90 cents for electricity for 1 yuan. If someone like me who is just playing around continues to use the big mining machines in the mines to mine, that would be called falling!

Because the world is always changing.

USB mining machines have always existed, but whether it is Roasted Cat, Ant or Pumpkin Zhang, the USB mining machines launched in the past are limited to using the power supply of the USB interface itself, the size of a USB flash drive, and can only accommodate one chip (often with a reduced frequency). Of course, this kind of mining machine is not worth playing with, and can only be used as a keychain.

U3 is different. I think it is very suitable for using the company's free electric mining in the office for the following reasons:

1. The computing power is large enough - a single 59G, I have three, that is 175G, and the daily income is more than two yuan. If a 1T dragon mine uses 0.5 cents per kilowatt-hour of electricity, after deducting the electricity fee, the daily income is only more than two yuan.

Did you see that? The actual daily income of 175G U3 is the same as 1T Dragon Mine!

2. Low noise, small size, low power consumption - I don't need to say more about this. It must be low noise and small size to be suitable for office mining. Dragon Mine or Antminer S4 make as much noise as a helicopter. Even if your colleagues don't mind the noise, the high power consumption is not suitable for long-term use in the office, and there is a fire hazard. I have personally seen a mining machine with more than 1,000 watts. Because the power cord was not of good quality, the power cord was burned and exploded. I was shocked at the time.

3. Realistic price - the price dropped to 115 yuan yesterday, and the power supply is also free for delivery. On average, it costs less than 2 yuan per GB, and the price per GB is almost the same as that of Antminer S5, and much cheaper than Avalon 4. In the past, the price of USB mining machines was unrealistic, so it was not worth buying, unless you don’t care about the few dozen yuan and just want to buy a toy.

I have said so much before, but in fact, a slightly older miner can understand it at a glance, it is a very simple truth. What I want to express is: mining in the mine will end sooner or later, no matter if you are 1 cent or 2 cents, there will always be a day when you lose money; while mining in the office is 0 yuan electricity, I will laugh longer than you.

A little tip: How to run multiple U3s on one computer?

I don't know if other people have the same problem as me:

In Windows XP, if two U3s are plugged into one computer at the same time, the drivers will conflict and cannot be used at all;

Although there will be no driver conflicts under Windows 7, if you plug multiple U3s into one computer, the program will crash as soon as you open cgminer.

In short, it is impossible to run multiple U3s simultaneously on a single computer.

Later I found a solution, and it was very simple: plug in only one U3 at the beginning, open cgminer, and wait until the hashrate appears before plugging in the second U3 to the computer; if you have a third U3, wait until the second U3 produces hashrate before plugging it in. It’s that easy. . .

Of course, this is a stupid way. You can also disable other U3s in the device manager and keep only one. Then enable other U3s one by one after the computing power is generated.

How to properly place U3 in the office?

I was a little shy at first, afraid of being seen by my colleagues, so I stuffed all three U3s into the gap between the small cabinet and the desk, and they just fit, as shown in the picture below.

Later, I found that this was a big problem. In an open environment, the heat generated by the U3 was actually very small, and the iron cover on the outside was not very hot during operation. However, once placed in this gap, it was found that there was a big problem with heat dissipation, and all three U3s became very hot. What's more serious is that the desktop and the small cabinet were all heated up, and even affected the colleague next to him, and the documents in his small cabinet were heated up.

In the end, I had no choice but to put it on the desk, stacked behind the monitor, and it didn't have much of an impact.

In fact, the noise of U3 is quite obvious, but it is completely suppressed by the noise of the central air-conditioning and has no sense of existence at all.