Bitcoin Forum

Of the rigs I could have under power and hashing within 1 or 2 days, which ones have the best ROI.

You can find links to several Bitcoin ROI calculators here:

https://en.bitcoin.it/wiki/Profitability_Calculator (https://en.bitcoin.it/wiki/Profitability_Calculator)

I don't think you're going to be able to get your hands on ASIC hardware in 1 - 2 days, at least without paying a huge sum of money and risking anything posted on eBay, etc being a scam.  I can't speak the the availability of FPGAs, but I don't think you're going to be able to get them in 48 hours. either  Someone with more experience there may be able to correct that assumption though.

Removing those two options, you're left with GPUs, and there are a wide range of options there from the higher-end AMD 7970s to the older, but arguably (at least historically) better hash-to-cost ratio cards like the AMD 5830s.  You have to account for different power draws, etc

I have used this site often in the past to get some ideas of mining rates, power, suggested settings & overclocking for different hardware options, so you may find some value here as well:

https://en.bitcoin.it/wiki/Mining_hardware_comparison (https://en.bitcoin.it/wiki/Mining_hardware_comparison)

Due to the insane costs of BTC @ $138/BTC, a $100 HD 5830 @ 300 MH/s @ 120w @ $0.11USD/kWh has a ROI of 37 days. This of course is dependent upon the BTC price maintaining such a high price and the difficulty not increasing much more. If the price continues to jump at a similar rate to the difficulty then it may be possible to maintain this ROI. If the price crashes to $40 but difficulty doesn't change much(which it won't due to energy efficient ASICs making up a large chunk of the network) then you are looking at a 195 day ROI. It'd be a weird time to fire up a new GPU rig but you might be able to make some money from it.

I have an Avalon on order.  The price of BTC is crazy high, there is still snow on the ground so waste heat is not an issue.  I just had the crazy thought that a lightning buy and coin-mine might give me a free graphics card or even some profit. 

I'll eBay & Target on the 5830.  Wish I lived close to a Fry's.

Was at Fry's yesterday  :)   Powersupply took a dump.

Im in the same boat mac...cant get in on ASIC's right now..but that didnt stop me from slapping another 7950 on my rig. There is still money to be make over the next 3-6 months with gpu mining. Feel sorry for the folks that stripped their farm to get "ahead" of the market glut of used gpus/fpgas. Very happy to be making .1btc per day now.

I have an Avalon on order.  The price of BTC is crazy high, there is still snow on the ground so waste heat is not an issue.  I just had the crazy thought that a lightning buy and coin-mine might give me a free graphics card or even some profit. 

I'll eBay & Target on the 5830.  Wish I lived close to a Fry's.
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I haven't seen 5830s via retail in many months, probably closing in on a year.  Sorry, my previous reply probably hinted at otherwise.  You may be able to find them online, but I've not looked. 

You can get multiple different 6000 series and 7000 series cards at the Fry's and Micro Center stores local to me, but the only 5000 series cards I've seen there in quite a while is some very low end card that's not suitable for mining.

I'm quite sure you could have a free card, with current BTC prize ROI is likely in 30/40 days depending on the card. Even if it's true the potential reward is not so high, for us "true believers" every bitcent is worth it. You know, today's pocket money may be tomorrow's retirement money ;)

With current hashingpower Difficulty will increase every 7-8days, I doubt it will stay for 30days to reach the ROI.

I bought my 5830 back in August 2012. There was a talk on the internet about incoming ASICS and doubts about ROI for GPUs even then. Nevertheless my 5830 paid for itself multiple times already when it was first mining BTC at 0.4 coins a day back then and now it is mining LTC at 2 coins a day.  Once you start considering that this card is very good for other crypto-currencies mining, the choice would be clear.

My cards mines 330MH of BTC or 320KH of LTC.

Use those numbers over here: http://allchains.info/calc.html (http://allchains.info/calc.html) to see you ROI

The difference is that back in August, no ASICs had shipped. Now, there are ASICs out in the wild, and there are more showing up all the time. Diff is going up pretty drastically. So is the price, for that matter, but still.