Bitcoin Forum

After reading, lots and lots of reading and help from some people on this board I think I am almost on the right track but would need some advice from some more experienced than myself.

I am going to mount it on a test bench

http://www.lian-li.com/v2/en/product/product06.php?pr_index=519&cl_index=1&sc_index=26&ss_index=127

With 4x 5830s.

This PSU

http://www.scan.co.uk/products/1250w-ocz-technology-zx-series-ocz-zx1250w-un-full-modular-80-plus-gold-92-eff-eps-12v-140mm-fan-atx

This motherboard

http://www.scan.co.uk/products/gigabyte-ga-990fxa-ud5-amd-990fx-s-am3plus-ddr3-sata-iii-6gb-s-raid-sata-pcie-20-(x16)-atx

Would like advise on a CPU and how much ram is required?
Also should I use a HDD or USB stick?

Also is there a way to minimise dust/dirt getting into this with it being an open air setup? Any advice greatly appreciated

GPU mining doesn't use hardly any CPU or RAM, so get whatevers cheapest! A lot of people run their miners on those single-core Semprons and 1 or 2GB of RAM. USB or HDD doesn't matter, just use whatever you have or whatever you can get for cheap.

As far as dust goes, there's not much you can do.

Thanks, so would this CPU be sufficient? And 2GB ram ?

http://www.ebay.co.uk/itm/AMD-Sempron-145-2-8GHz-Single-Core-Processor-/160866488198?pt=UK_Computing_CPUs_Processors&hash=item257463cf86

Also is the PSU I have chosen overkill for 4x 5830s, would a 750 be sufficient?

If you are running 4x HD5830, does each have 2x6pin PCIe connectors? I find that the hardest thing to get right with a PSU, even the 1250w you mention below only has 6x PCIe power connectors I believe, OCZ 750w only has 4 if I remember correctly.

Did you pick up the 5830s 2nd hand?

I donno if I would go as low as a single core Sempron! I have only mined on high end rigs though and use the CPU for Litecoin leaving at least 2 threads free for GPUs, if you go too skimpy on the CPU it may affect GPUs running at their full potential.

Thanks for your reply, really appreciating all the help I can get.

I have not purchased anything yet, this is advice I have already been given/info I have read which is going to suit my budget. I would be probably picking them up second hand on ebay.
Any other suggestions always welcome.

Oh, OK, well 5830s are nice cards but getting hard to find new, since you will be running them 24x7 I suggest you go new with warranty.

Good deals can be had on 6950s which are 400MH+, 7970s do 500MH+ but are very expensive.

Well,lets check the CPU support list :

http://www.gigabyte.com/support-downloads/cpu-support-popup.aspx?pid=3891

Bottom of the page  ;)

http://www.gigabyte.com/products/product-page.aspx?pid=3891#ov

Yes,it will work on that mobo with BIOS version F2  ;D

Your mobo (when you receive it) may already have that version installed,try firing it up & if it won't,then you'll need to flash the BIOS to version F2.

Gigabyte makes it VERY easy to flash  ;D

Opps,most newer BIOS versions are "backwards compatible",so it should work with any newer version installed at the factory.It looks like it comes version F2 though.

BTW,I picked up a 7970 :

http://www.newegg.com/Product/Product.aspx?Item=N82E16814129264

On sale & 12% off too,$368,does 610 mh without breakin a sweat  8)

Keep lookin,there are deals out there,just gotta look.

I would recommend the 7970. Runs cool and can do 650 easy. It will hold it's value much longer and be more useful in the long run. Depending on how expensive the 7990 will be that might be an option also.

Just to make sure you are not overlooking something obvious.  It is after eleven and closing in on midnight, you know this right?

 - http://bitcoinclock.com

At the stroke of midnight (less than 100 days away), the block reward gets cut in half to 25 BTC per block.

(i.e., unless you are paying like three cents a kWh or less, why would you be buying GPU hardware specifically for mining at this late state in the game?)

This late in the game if your gonna buy anything it should be a GPU or nothing at all until January or later. The GPU's are very versitile and have plenty of exit options. FPGA's are pretty much only good for bitcoins and have unreasonable shipping times along with initial cost. With a GPU if you don't mine something else with it when it's obsolete you can probably resell it at a profit worst case scenario. Any other option has higher up side but even worse down side. I'd wait until January or February to see how things are if your gonna invest in other technologies.

Nothing at all is the best advice. Spend your investment directly on coins.

Until the Pirate situation is resolved i wouldn't touch coins directly. That's probably the worst option at the moment.

My electricity is included in my rent as long as it is considered fair usage (i.e my landlord doesnt notice the costs suddenly rise by 400%) so running 1 rig will be fine and free.
I am chosing a dedicated mining rig because of the long shipping on FPGAs and like others said the exit strategies of being able to sell the GPUs.
Hopefully I should be able to almost break even with BTC in 3 months and the profit would be made on selling the hardware.
After that I will probably look into ASICS

There's little to no chance of you coming close to breaking even in 3 months. The "little" part would only be possible with a much larger upwards jump in price vs difficulty - and if that's what you're counting on, you will be a lot better off buying coins.

Why will I not come close to breaking even in 3 months with free electricity??

1) There is currently a steep rise in difficulty as FPGA rigs are currently being delivered and added to the network power.
2) GPU mining has a significant learning curve
3) We barely have more than 1 month left until BFL says they will start delivering ASICs rigs. While that's certainly no guarantee, it's another thing you're betting against.

You're about to invest a lot of time and energy for very little return.

Maybe I am missing something - which is why I am posting here in the first place instead of going out and buying everything without researching but 4x 5830s will give me about 1200 mh/s (right?) which will generate at current difficulty approx 0.5 BTC per day (right?) which means 15 coins per month. So say the difficulty does start to increase and it generates 40 coins over 3 months that is again at current prices about $400.

The hardware it seems I can get for around $600 all in.

I should be able to resell the hardware for about 60-70% the price I paid for it meaning a $125-150 profit or approx 20% ROI

This seems worthwhile to me 20% ROI in 3 months, if my figures are correct but maybe I am wrong again which is why I am posting this before I rush out and buy the gear.

If your energy cost is free GPU's are the only way to go, if you're not gonna wait any longer. Your on the right track if you want to get your feet wet with the least risk. I decided to go with a 7970 cus i can game with it even years down the road, and i don't wanna get involved in 4+ card setups.

Where are you going to get the 5830's? Used?

Have you ever gotten a machine running with 4 video cards maxed out at once before?

Are you going to run linux or windows? Have you ever flashed a card bios before? Are you familiar with the overclocking tools?

"IF" the difficulty "starts" to go up? The difficulty just went up over 11%! It's been making large increases every round for months. FPGA deliveries are ongoing.

What you're missing is experience dealing with GPU mining. What I'm telling you, as someone who has been GPU mining for over 19 months, on many rigs, using many software and hardware options: what you are proposing doesn't sound like a good idea. If you want to invest in Bitcoin, you should buy coins. If you want to invest in mining equipment, either gamble on BFL or gamble against them (buy FGPAs from another manuf and pray BFL fails to deliver.)  

Best of luck!

Just be careful with used Sapphire 5830s with the single 92mm fan. I see plenty of those on Ebay. I bought a bunch of them new 14-18 months ago and about 40% of them have failed within the last couple of months because of seized bearings. It may just be my luck, but something to consider when buying used cards.

GPU mining Bitcoin window is closing now, either wait for ASICs to come into the game around October or try GPU mining Litecoins and either keep them or sell for BTC.

Problem is even if I order now I will not get them even close to October so that ship has sailed also.
I just want to get in now

I bought a 5770 7 weeks ago that paid for itself in 6weeks(not counting electricity), I just sold it because I'm moving xcountry so ended up with a 100% return on investment.  Your numbers are good I believe, and 5xxx cards are a good choice so go for it. 
disclaimer: I started mining just as the price started spiking and my pool had a long streak of good luck so don't expect as large of a return as I had.