Where do you get these numbers from?
Assuming you invested $1000 in a rig and managed to somehow get 4x 5850s (they're hard to find) and managed to get it up and running this instant you'd only have 6 days left at this difficulty level, or 13.8 BTC (assuming you hopped on a lucky 0% fee pool). Next difficulty is going up about 30% (probably more) so you'll see a 75% rate of coins for the next 10-12 days. Depending on how many more people jump on board difficulty will go up again.
Bitcoin prices might rise, they might fall, who knows. There are no guarantees in this game.
Assuming you invested $1000 in a rig and managed to somehow get 4x 5850s (they're hard to find) and managed to get it up and running this instant you'd only have 6 days left at this difficulty level, or 13.8 BTC (assuming you hopped on a lucky 0% fee pool). Next difficulty is going up about 30% (probably more) so you'll see a 75% rate of coins for the next 10-12 days. Depending on how many more people jump on board difficulty will go up again.
Bitcoin prices might rise, they might fall, who knows. There are no guarantees in this game.
AMD motherboard with 4x PCIE slots, AMD CPU, 2GB DDR3 memory and 4x ATi 5830 graphics cards, an 850W Power supply and any old hard drive with windows XP or newer
Be mindful of the physical location of those 4 slots, lest you have to use risers. Make sure the power supply has enough connectors for the cards you buy. Linux is worth considering for a dedicated mining box.
Revenue in 1 month frame: 1623.67 USD
Revenue minus power costs: 1577.10 USD
Hardware break even: 19 days, 7 hours
Net profit first time frame: 577.10 USD
That doesn't tell me WHERE you got 1623.67 from. You could have just said "83498934" for all that tells me.
Just for fun I'll show you what I mean:
4x 5830s = ~4*285 (you may get more, you may get less, this is a reasonable average) = 1140MHash/sec.
1140MHash/sec = ฿2.02 /day on a low variance, 0% fee pool with average luck. I'm going with averages here, so let's go with that.
Next difficulty increase is in ~6days, so 6days * 2.02BTC/day = 12.12BTC (if you started mining RIGHT NOW, this is optimistic as you dont even have the equipment yet)
Next difficulty projected @ 733627 (likely to be higher but this is what we have now)
1140MHash/sec @ 733627 = 1.56BTC / day
1.56BTC /day * 10 days (avg time @ difficulty lately) = 15.6 BTC
Next difficulty could be whatever, lets go with 30% again
1140Mhash/sec @ 953715 = 1.2BTC /day x 10 days = 12BTC
12.1 + 15.6 + 12 = 39.6 for a 26 day window (close enough to a month). Assuming coins to be @ $35/coin (could be more, could be less) x 40 coins = $1400. If coins are $45 you make $1800 if coins are $5 you make $200.
This is an optimistic guess assuming lots of stuff goes your way and you can your rig up and running today but it can give you a feel for your diminishing profits and variability based on coin price.
Someone posted it for me based off of 4 grx cards
http://bitcoinx.com/profit/index.php
