Quote from: kanta on May 23, 2013, 02:05:52 PM

Quote from: vs3 on May 23, 2013, 09:05:25 AM

Quote from: mrm0 on May 23, 2013, 08:23:49 AM

Quote from: Lucko on May 23, 2013, 07:11:53 AM

Anyone have experiences with those?

https://bitcointalk.org/index.php?topic=195540.60

There are other group buys but I'm looking at this one since it is EU and relay low price.

Hmm...

Presently at Slush I get approx. 0.002BTC@~600MH/s at each block (averaged). We find around 16-18 blocks per day.
Assuming I were to pay 2.2BTC for this usb 'block eruptor' I would be looking at:

2.2 / 0.001 / 17 = 130 days to break-even, assuming network difficulty remains as-is, which it WILL NOT.

Because estimates of rate of difficulty increase vary wildly I hesitate to _speculate_ further, but it seems to me that there is a possibility this buy will not pay for itself in a reasonable time frame.

There are two more things to consider - let me use some examples:
- I have 5850 cards which use about 80-85W to produce roughly 300MH (or say it the same as that USB key). Here is the USB key advantage - it uses 0.5W.
- I got my cards at $120-150 each. Some are on dedicated mining rigs, some are used for gaming. At the end of the day I can sell those and recoup some of my investment.

My observations about payout are similar to mrm0's - with one rig at 900MH/s my average is about B 0.035-0.04/day (depending on luck). Or it will pay itself off in about 160-200 days (at current difficulty levels).
A GPU card (priced let's say 1.1BTC at current levels) making the same 300MH/sec minus price of electricity (2KW@$0.15=$0.3 or B0.0025) will bring you B 0.01/day or given the same presumptions will pay itself off in 100 days.
So, after the same 200 days each of those cards will pay itself and bring me about $120-150 profit + I can sell the cards for let's say $75 = total profit $200/card.

I'm over-simplifying it but you get the idea.

Bottom line is - if you're just now entering the mining world it is probably not worth the money as there are better alternatives.

EDIT: See this site for calculating the break-even duration: https://bitclockers.com/calc

I agree. I just got into mining, and I even upgraded the GPU in my PC to a 7970 with the intent of mining faster than my GTX 670 could do. However, I didn't buy the card (nor assemble the computer) for the sole purpose of mining, and at the end of the day, I have a badass gaming rig that I can play any game maxed out, which is why I built my rig in the first place. I'm not worried about making my investment back, so long as I don't spend more on electricity than I make mining, which I am currently doing pretty good at (700 MH/s). That and the 7970 came with 3 games that I had really been wanting to play.

Well I didn't ask if it is worth buying I asked if anyone have it. And there are errors in calculation. 5850 never uses only 80 to 85W. It uses 150W at stock and 165 to 191W at 300. Look at https://en.bitcoin.it/wiki/Mining_hardware_comparison There are some errors but you can notice them at once.

And I know it is overpriced but this one you can get right away. I know I can get BFL 5.5 for 2BTC but when? This year? Next? I know I can get Block Erupter blade for 50BTC and the same Ghash rate with Block Erupter USB would cost 80BTC. I know that Block Erupter blade is also to expansive so USB is even more. But saying all that I don't have 50 BTC and I don't have money to buy them. And probebly with the same logic it doesn't pays out to have it. So this is cheap alternative to get ASIC. So it is not question if I will buy. It is only question if someone have it to report how it works?