Building a Miner Resources

[george357]

Just remember to have a beefy enough CPU with atleast 2 cores to supply work for those GPUs, specially if you go 2x7990 or more. And as I said earlier, 4GB of RAM is not enough for that amount of GPUs on anything else than SHA256 mining. Plan on having +1.5GB/GPU of RAM (7990 might need +3GB/GPU) for scrypt. You can find more info in scrypt mining in other topics regarding CPU and RAM requirements.

Corsair 1200AX is something to consider, someone said not to cheap on a PSU and still they offer 1000W unit when you talk about top-end 7990s and 7970s 

I'm using my rig also for hashcat so I understand your point of not making just a bitcoin miner. I used to run BOINC too some time ago.

Thanks for the input! I am probably going to use an AMD 6-8 core processor to start with considering that they are realtively cheap and have a good general utility for the cost (of course with an open system design such as test-bench, this can be swapped out on a whim if a more powerful CPU is ever needed for anything). RAM, being one of the cheapest components, I was looking at 8GB minimum which also adds to the multi-use aspect. I will also check out the Corsair you recommend.

That hashcat looks pretty cool, I had not seen that before. I am hoping to get back to BOINC at some point, I would really like to have three to five rigs to cover differing specialties at some point i.e. a miner, HTPC, BOINC, General Use, but that is not happening anytime soon which is why multi-use is important to me.

[mokahless]

Thanks for the input! I am probably going to use an AMD 6-8 core processor to start with considering that they are realtively cheap and have a good general utility for the cost (of course with an open system design such as test-bench, this can be swapped out on a whim if a more powerful CPU is ever needed for anything). RAM, being one of the cheapest components, I was looking at 8GB minimum which also adds to the multi-use aspect. I will also check out the Corsair you recommend.

That hashcat looks pretty cool, I had not seen that before. I am hoping to get back to BOINC at some point, I would really like to have three to five rigs to cover differing specialties at some point i.e. a miner, HTPC, BOINC, General Use, but that is not happening anytime soon which is why multi-use is important to me.

I personally think it is a mistake to dedicate the unit to tasks other than mining. You will lose efficiency and increase the chances of downtime.

Also, you seem to have mistaken my reason for choosing the APU in my recommended setup: It was because I believed the extra $17 to be worth the extra MH/s the GPU in the APU would give.

[george357]

I personally think it is a mistake to dedicate the unit to tasks other than mining. You will lose efficiency and increase the chances of downtime.

Also, you seem to have mistaken my reason for choosing the APU in my recommended setup: It was because I believed the extra $17 to be worth the extra MH/s the GPU in the APU would give.

Nah, the CPU I quoted was a mistake, I was thinking the A10-5800K was a 6-Core http://www.newegg.com/Product/Product.aspx?Item=N82E16819113280
but it is a four-core. Which at ~$129 is probably what I'll use.

The 8-core was in reference to the FX-8350 which looks good to me for ~$200 if I decided on a dedicated CPU instead of the above (not likely at this point).

I am not planning to use the unit for multiple operations at once, I am looking at the options I have other than mining when building the rig. The "rig" must be usable for other things (at different times) for me to justify the investment. That may be where there has been some confusion in this thread for which I apologize.
The best way for me to explain it is that I am looking to put around ~$2250 into this rig. I am going to run it as a miner for BTC initially and see how that goes, if/when the ASICs make this irrelevant I plan on mining LTC or TerraCoin, which if I understand correctly can be done on both the GPU/CPU with the right miner software. Now if I decide to quit mining or want to go to an ASIC in the future, I can either dedicate the rig back to BOINC or I can remove one of the 7990s from this rig grab another CPU and have two pretty nice rigs, one for gaming/video encoding and one for BOINC/CAD work. This would work real well especially since I don't use CAD enough to take away from BOINC. Hope this clarifies my intent!

Of course any further discussion is welcomed the more input the better. 

[KJaneway]

I believe it's too late in the game for GPU unless the price of BTC skyrockets another 100% from current prices ($150)...
I agree with you about the ASIC having a single purpose, however, GPUs will have a single purpose soon as ASIC gets deployed.
The only reason I keep mining is because it's profitable for me since I already paid for my GPUs and rigs a while back, especially at the current BTC prices.
Makes little to no sense to invest $1700 in a rig that won't get a return of investment anytime soon.
At the most, you'll be mining 3.5 GHash per Rig (given you install 4 high end GPUs such as 7990's) and even then, that's a $4000 rig easily and you'll be making 0.30 BTC a day 9 BTC per month at current price/difficulty you're looking at 6 months ROI and that if if the difficulty remains the same, which it certainly won't after ASIC is fully deployed... so maybe you'll have an ROI of a year or more...
the 7990's you can't get them for less than $800 and I don't see ANYONE selling an used high end top of the line card for any other reason than being broke and needing the money or to buy drugs! LOL

I totally disagree with you. The ROI of such a machine would be perhaps 2 month or so. You have to take into account that, unlike ASICS, these GPU Miners are not a one-way investment. Yes you are right: You spend 4000 Bucks for hardware. If you make 9 BTC in the first month, you would have around 1500 bucks at the current price. Even if you need to month for that goal, you can easily sell these cards to other miners or, what is more important, gamers. There are always enthusiasts who pay 80% of the original price for used GPUs. So you would get around 3000 Bucks from your 4000$ investment. That makes it profitable very soon. And from that break even point you can decide each time to sell the hardware. Luckily bitcoin mining is actually much faster than decrease of your hardware value.

Just my 2 cents.

KJ