Cheapest rig for cross fired 5870's

Gullanian · 14 Jun 2011 at 00:13

I want to cross fire 2 of these to run at 100% days on end:

http://www.overclockers.co.uk/showproduct.php?prodid=GX-147-XF

Is my BeQuiet 650w PSU good enough for this?

Also, what is the cheapest Mobo I can buy that will fit these cards and a AMD 1090T x6 Processor?

Thanks for the help, would love to order this tommorow.

Surveyor · 14 Jun 2011 at 00:16

Gullanian said:
I want to cross fire 2 of these to run at 100% days on end:

http://www.overclockers.co.uk/showproduct.php?prodid=GX-147-XF

Don't you ever sleep?

Or are you still Bitcoin mining?

stulid · 14 Jun 2011 at 00:16

You PSU is enough.

These are the cheapest mobos in order of best chipsets, as long as its a DDR3 board your looking for?

790X - http://www.overclockers.co.uk/showproduct.php?prodid=MB-168-GI&groupid=701&catid=1903&subcat=1481

890GX - http://www.overclockers.co.uk/showproduct.php?prodid=MB-010-SP&groupid=701&catid=1903&subcat=1782

990X - http://www.overclockers.co.uk/showproduct.php?prodid=MB-349-GI&groupid=701&catid=1903&subcat=2046

Reaper 392 · 14 Jun 2011 at 00:17

bequiet PSU should be just about enough if you dont have too many HDD's or DVD's or whatever, although a 700W+ PSU would be preferable:
http://www.anandtech.com/bench/Product/300

do you have the cards already, or were you planning on buying them?

Gullanian · 14 Jun 2011 at 00:24

Surveyor said:
Don't you ever sleep?

Or are you still Bitcoin mining?

My sleep pattern is rubbish, I have trouble sleeping sometimes! I found out these cards give excellent £/BC rate, better than most other cards which makes it within the realms of decent profitability if I get them quickly.

Gullanian · 14 Jun 2011 at 00:25

Thanks for comments will look at them properly tommorow!

Reaper 392 · 14 Jun 2011 at 00:30

your getting the cards simply for bitcoin?

how long will it take for those cards to pay for themselves?

Surveyor · 14 Jun 2011 at 00:35

Reaper 392 said:
your getting the cards simply for bitcoin?

how long will it take for those cards to pay for themselves?

The OP was considering dual 6990's :eek:

Dual ATI Radeon HD 6990 setup

Gullanian · 14 Jun 2011 at 00:40

http://bitminer.info/ (figures quite under what can be achieved with some basic OC afaik)

I have a solo 5770 at the moment which works at a rate of 170mhash, overclocked this can go to 190mhash but I'm not too good at OCing and it's unstable but with some skill I'm sure you could get it to 200mhash.

I've heard that a 5870 can do 400mhash/s, 2 of them = 800 mhash/s.

Check out here:

http://bitcoinx.com/profit/

Electricity wise you're looking at £1.50-£2 a day. A 5870 can do ฿0.56 a day, 2 of them + OCing = ~฿1.20 a day.

BC is currently worth ~$20 each, (https://mtgox.com/trade/buy), I'm also gambling a bit that the value is going to increase as well, I'm trying to gain BC for medium term investment (~4 months or so).

So at $20 each you are earning ~$24 a day, minus $4 a day in elec = ~$20 clear profit. Cards are ~$400 total for 2, which means in 20 days they pay for themselves (and they have obvious resale value).

Gullanian · 14 Jun 2011 at 00:40

Surveyor said:
The OP was considering dual 6990's

Dual ATI Radeon HD 6990 setup

Yeah I was, just can't quite pull the trigger it's over extending me too much, I think 5870 is a good compromise.

stulid · 14 Jun 2011 at 00:42

It wont be over extending me to much if you want to buy me a 6990?

Gullanian · 14 Jun 2011 at 00:46

Dual 6990s should be able to pull B2.50-3 a day which is phenomenal, ~$50 a day at current rates. It's just going to take ~50 days to pay them off which is too long a time frame for me for that cost. Also, they are in short stock in a lot of places (especially USA apparently) for the specific reason of bitcoin mining.

Gullanian · 14 Jun 2011 at 00:52

http://bitcoinx.com/profit/index.php

Difficulty : 434883.00
Hash rate: 800000 (2x5870)
$1k setup cost
$0.30c p/h electricity
$20 conversion rate

= 30 day break even

So tempting just to buy this right now, I think I'm going to have to just go for it.

Gullanian · 14 Jun 2011 at 00:54

By the way, if Bitcoins crash which isn't out of the realms of possibility, look out on ebay for an influx of discount 6990's.

Surveyor · 14 Jun 2011 at 01:00

Gullanian said:
By the way, if Bitcoins crash which isn't out of the realms of possibility, look out on ebay for an influx of discount 6990's.

Discounted because they've been thrashed 24/7 for weeks or months on end.

And probably using the Extreme Performance BIOS which invalidates the warranty.

No thanks.

stulid · 14 Jun 2011 at 01:10

Is this bitcoin thing for real? what data are the cards crunching to make money?

Gullanian · 14 Jun 2011 at 02:10

stulid said:
Is this bitcoin thing for real? what data are the cards crunching to make money?

Yes, it's real, but you might be buying into a greater fools theory:

http://en.wikipedia.org/wiki/Greater_fool_theory

Too early to tell.

Check MtGox.com for market prices, those are live actual prices you can trade BitCoins for USD. It's extremely volatile.

stulid · 14 Jun 2011 at 02:19

But what is the work being done to make these bitcoins?

I understand what was SETI, search for a signal out of snippets of data.

I understand Folding at home.

Gullanian · 14 Jun 2011 at 02:29

I admit my knowledge here is a bit hazy but as far as I know it's double SHA256 hashing a block header as part of a process of block generation.

We have mentioned in the previous section that adding a block to the block chain is difficult, requiring time and processing power to accomplish. So what incentive does anyone have to spend the effort to produce a block, if it takes up all these resources? The answer is that the person who manages to produce a block gets a reward. This reward is two-fold. First, the block producer gets a bounty of some number of bitcoins, which is agreed-upon by the network. (Currently this bounty is 50 bitcoins; this value will halve every 210,000 blocks.) Second, any transaction fees that may be present in the transactions included in the block, get claimed by the block producer.

https://en.bitcoin.it/wiki/How_bitcoin_works

Gullanian · 14 Jun 2011 at 08:37

How does this look?

XFX ATI Radeon HD 5870 1024MB GDDR5 PCI-Express Graphics Card

Sapphire Pure CrossFireX 890GX (AM3) Motherboard - Retail

Corsair Enthusiast Series TX 650W V2 High Performance Power Supply (CMPSU-650TXV2UK)

AMD Sempron 140 2.70GHz (Socket AM3) Processor - Retail

Corsair Value 2GB (1x2GB) DDR3 PC3-10666C9 1333MHz Low-Voltage Single Channel Module (VS2GB1333D3)

I have a case + HDD's spare. Still a bit too expensive @ £520