Bitcoin Forum

I’d like to warn anyone wishing to buy USB ASICs.

Don’t do that if your goal is to get profit.

I bought one because wished to take part in mining and to be proud that I also make a contribution (although almost negligible) to the security of Bitcoin network, and I don’t possess a big computer to stick a powerful graphics card into.

And given that wish I am kind of satisfied.

But in economic terms, even though I bought it at a price equal to ฿1.2, even with current difficulty it will take more than 6 months to pay back. Of course as I payed in fiat, I can hope to do that faster if Bitcoin price rises. But I would better just buy ฿1.2 on a market instead if I cared about profit only.

USB mining is an obvious dead end. Mining is fungible and prone to economies of scale, you will only survive with a massive datacenter, the best ASICs on the market tightly packed on the cheapest boards powered with the cheap energy. Large discounts for purchases, effective workmanship etc. enable you to undercut the competition by pushing more GH/s for a given BTC price. You get more of the mining pie and maybe a thin profit margin.

Compare this with an USB stick where the form factor alone (with USB controller and connector, plastic case etc.) has increased the price 10x as compared with the bare mining chip. Nevermind that in order to run say 10 USB dongles drawing 2W each, you need to power a whole desktop computer with at least 50W.

And if you do intend to buy one anyways:  they get HOT

Be careful touching!

Hope in winter that’ll help a little.

Especially when you have a 'usb farm', the need some fans or something.

You can run 1 (ONE) without a fan.    But a fan won't hurt.

Unless anyone has heard of burnouts from running without a fan?

Personally no. But if you use several in a hub, safer to use a fan. I don't think you want to risk it.
Especially in the summer.

I have heard of fans burning out  ;D     The cheapy USB fans sometimes don't last long.

Does it scale or returns remain the same (e.g., 1 usb ROI is 6 months, how about 2? 3?)

I'm very new to this, not doing for profit, but for the geeky aspect of it.  I'm planning to run my NAS with this usbs, but not quite sure the 'optimal' number of usbs you can run (without breaking the bank)

There are some charts showing the profit from having 10 USB ASICs and they look a lot better than GPU. With increasing difficulty GPU's will become inefficient in the few months at least in BTC. USB on the other hand should generate some profit at least till the end of the year.

Any link to them charts?

I had a BFL Jalapeno arrived last week but I sold it off.
https://bitcointalk.org/index.php?topic=233486.0

Also planning to get them Block Erupter USBs to test them out, even thought ROI is a far thought.

Here is one of them (unfortunately in polish) showing the estimated PLN mined in the next months using 9 USB ASICS with 10% difficulty increase. On the other chart they did something similar with 5x7970. GPU's seem to only be worth it if you have free electricity.

http://minercharts.com/pl/?prod=3024&cons=23&title=9%20x%20Asicminer%20Block%20Erupter%20USB%20-%20op%C5%82acalno%C5%9B%C4%87%20kopania%20Bitcoin

thanks. excellent calculator.