Topic: Advice from someone who isn't a moron (Read 6602 times)

I would recommend a larger power supply for 3x7950's... Would suggest a 1000 - 1250 w of a good brand.

Hello all,

I want to place an order on this setup what do you think ? no open case available in my are.

..and i plan o mining litecoin

CPU: AMD - Procesor AMD Athlon II X2 Dual Core 250 (C3) (BOX)
MotherBoard: GIGABYTE 990FXA-UD5, AMD 990FX + SB950, AM3+, DDR III, USB 3.0, PCI-E 16x, SATA III
PSU: Antec HCP-850, 850W, Modulara, Vent. 135mm, Efficiency 92% (80 PLUS GOLD)
Ram: Corsair Vengeance DDR3, 2x4GB, 1600Mhz (Dual Channel)
Case: CoolerMaster - Carcasa CoolerMaster HAF 932 Advanced
Hdd: some old suff i found at home
Video Card:3 x Sapphire Radeon HD 7950 Boost, 3GB, GDDR5, 384bit, DVI, HDMI, Mini-DisplayPort, PCI-E 3.0

Cool! Thanks for this

That's what I'm doing. It works just fine with cgminer.

This chart offers benchmarks, though I can't vouch for them:

http://media.bestofmicro.com/G/Y/355714/original/0101%20Bitmining.png

Derp derp I didn't see that - thank you

Ya I included all of my maths in the bottom row so anyone can replicate it. Just do some testing with you hashrate and power draw, and plug them into excel.

Two rigs.

6 x 5870 > first rig,
4 x 7970 > second one.

Good information. Is that just a single rig? How many cards total on that?

The recent BTC price surely is helping, but not by much, at least is not helping me (with a mix of 7xxx + 5xxx cards @ 0.16 power cost).

Normal volting: 5290 Mh/s @ 2174W = 28.18 USD/day  (E = 2.43 MH/s/W,  Temps @ 67, Fans @ 80%) (7xxx@1.17V, 5xxx@1.2V)
Undervolting   : 4930 Mh/s @ 1700W = 27.51 USD/day  (E = 2.90 MH/s/W,  Temps @ 59, Fans @ 50%) (7xxx@1.09V, 5xxx@1.062V)

For 7xxx cards only (specifically 4 x 7970):

Normal volting (1.17V): 2800 Mh/s @ 1170W = 14.84 USD/day (E = 2.39 MH/s/W)
Undervolting    (1.09V): 2545 Mh/s @   788W = 14.55 USD/day (E = 3.23 MH/s/W)


Pros and cons

Well we are surely going to find out - hah! If not, oh well. I have a 2nd rig I could fire up and run the other two. Or, sell the 5850's and invest in another 7950. If you find any additional information about the potential incompatibility, let me know. Thanks


Yes, good idea. It may be more profitable to run them at full power, or overclocked and make more BTC/LTC. Your chart is phenomenal! Any chance I could get a copy of this spreadsheet? I'd like to use it for BTC, and then modify it for LTC. I love having all the numbers at my fingertips... (and I like to have provable numbers I can show my "accountant").

Woops forgot to include the chart. Click for bigger version.

Undervolting will undoubtedly help your PSU handle all those GPUs, but it might not increase profitability. Remember, efficiency and profitability are NOT the same. Here's a quick chart that I keep up to date with my 7970. It's not exact, but I adjust the PPS rates and the USD/BTC whenever I want to look at what setting is most profitable. I used to make more money undervolting, but with the massive increase in price, it's better to just flat out overclock and mine as many BTC as I can.

If 7950s are already undervolted to 1.09 VDC, and you undervolt the 5950s to similar or lower, the PC P&C will handle that no prob. But trying to optimize given your electricity costs probably a good idea. Going by hazy memory, I think my 5850s only got about 325 Mh/s mining BTC @1.05 VDC, as opposed to around 310 Mh/s @ 0.95 VDC, and the % diff in power draw was significantly more, so the extra 0.1 VDC wasn't worth it in my case.  

Edit: BTW, you sure you can run 79xx and 59xx together? I seem to recall people having a problem with this.

Just purchased a Kill-a-Watt today with the two 7950's I purchased
So yes, I will be trying this for sure.

What I mean is that undervolting increase efficiency, but (past a certain value) not necessarily increase profit.
You should try undervolting, but use something like http://dev.bitcoinx.com/profit or http://dustcoin.com/mining to calculate the actual profit.
A Killawat shoud help you very well.

Very welcome. I'm just a crypto-newb-moron trying to figure it out as well. Happy to share the little I've learned.



Interesting. Well in that case maybe I should just undervolt the 5850's, since those are already unvolted...

Not sure about undervolting the 7950.
A 7950 is basically a 7970 with some cores disabled and undervolted to 1.09V from 1.17V.

How low would you propose to go?

This is what I wanted from this thread.

Thank you too all who participated!

Again thanks to all - very useful information!

Dargo -  believe this is what I'm going to do. I will undervolt the 4x GPU's, and I believe the 7950's draw less power than the 5850's. If I need more molex connectors (which I don't think I should need), I'll let you know.

Again, thanks for the info... can't wait to get this up and running.

~FAT

If you undervolt the GPUs (which is what I recommend), the PC P&C unit will be fine. I was running 5x 5850s off mine no problem (undervolted to 0.95 VDC). If you want to run at stock voltage, you'll probably want a more powerful PSU, but IMO this wouldn't be worth the extra power draw. I think you will have enough Molex to go to 4 GPUs, but if you want more Molex connectors for fans or whatever, I have two SATA ---> Molex adapters I can sell cheap - just PM if interested. I was actually running the 5th GPU off these adapters, which worked fine for an undervolted 5850.  

Crazyates said it well..

The issue is only when you pull to many watts over one of that rails.  Lets say you have 500 watts PSU.
2 rails puts 250 watts per rail..  Now you plug in 2 GPU's and draw 300 watts on 1 rail..  well that's not gonna work or it will until you fry a PSU.

There is nothing wrong with multiple rails if you are going to be cautious about what is plugged in where.
Single rail, just plug it all in and go.

All of your previous recommendations were based off 3 GPUs, Now you're talking about 4 GPUs. With those 4 GPUs, you do want something over 900W, just to be safe. I would take that PC P&C one over the 4 rail Rosewill, but I don't know much about the reliability of the brand.

If I were building a 4 GPU rig, I would buy this: http://www.newegg.com/Product/Product.aspx?Item=N82E16817171056
Single rail.
4x 6 pin and 4x 6+2, enough for 4 GPUs without adapters.
More efficient.
I've had great luck with CM, and so have other people on here.
It's ~$45 more, but worth it, IMO.

Thank you Dargo, I'm going to take your advice on this one because I'm looking to buy a good PSU for powering the following in a single motherboard:

2x 5850
2x 7950

I need to get powered risers for these (x1 > x16), and I'm concerned about having enough molexes to power everything, but I think I should be good considering I only need them for the GPU's. I won't be powering fans since it will be an open case. Maybe I'll need to get a single 20 inch fan to help with cooling, but otherwise should be fine.

Crazy - I just saw your post while writing this one, do you think that the PSU linked by Dargo would handle what I'm trying to accomplish above? Looking forward to your response.

PSUs have what are called "rails", and it's basically a voltage regulator inside the PSU. You have a 3.3V rail, and 5V rail, and a 12V rail. Some manufacturers put mutliple 12V rails. When we're talking about multi vs single rail PSUs, we're only talking about the 12V rails.

Take a look at these two PSUs:





The top one is an OCZ 700W that has 4 rails. The bottom is a SeaSonic that only has 1 rail. Theoretically they're both around the same wattage, but you could not run 7970s or 5970s on the OCZ without some careful cable management and load-balancing.

Each of the OCZs rails are only rated for 18A. 18A x 12V = ~216Watts per rail. If you throw a pair of 6 pin PCIe power cables, and try to draw more than 216W, you're going to have issues. If you're running 5830s or undervolted 7850s, this prolly isn't an issue. However, a 7970 or a 5970 is going to crap out, and not be able to mine properly. It simply won't have the power.

Now the Seasonic on the bottom has a single rail at 62A, which gives us 744W to be shared among all the PCIe power plugs (and the motherboard, for that matter). So if you have a pair of cards that want to draw 300-350W each, it's no problem.

Multi rails can be beneficial, as a lot of times they're cheaper, and stay cooler. You also often times have a dedicated 12V rail for your MB, so powering your GPUs won't affect the Vdroop going into your MB. You can try to load-balance, say putting 1 plug from 12V2 and 1 plug from 12V3 into a 5970, and it will work. However, a lot of PSUs don't label which PCIe plugs are on which rail, so this load-balancing can be a PTIA, or even impossible sometimes.

This is great advice, except I'm not a huge fan of the PSU choice. A better choice IMO would be this

http://www.newegg.com/Product/Product.aspx?Item=N82E16817703028

It's a little more $, but higher power and better quality. Also, it's not modular, but if you go with an open air case (which you should), it hardly matters.

If you know how to do it, replace the thermal paste on the cards.
I recently used noctua's nt-h1 and WOW, what a difference!!! 

This is the part I'm fuzzy on - what is the advantage of a single rail vs the multi-rail PSUs? Just trying to learn the difference - thanks Gern, looking forward to your answer.

Get the best single rail power supply you budget will allow, it is not a place to save a buck when mining.
You will not regret having a good PSU. The rest is, well, what FatMagic said

Right on. Here is how far I've come with my own research in terms of products. I'm trying to keep my price down to get the startup going, and to make back my ROI over 3-4 months. Again, LTC build.

And please note, because you are starting with no extra parts on hand - the initial build will cost significantly more than it is costing me. I build PCs as a hobby, so I have lots of extra parts to frankenstein together. This means it will take much longer for you to get the ROI back. Maybe build this PC with the idea of gaming with it, and mining with it as well - so dual purpose, you get to game on an awesome rig, and you get to learn more about cryptocurrencies along the way... and make some cash. Maybeeee break even, maybe not.

GPU:
3x Sapphire Radeon HD 7950 - $269 / each

PSU:
Rosewill Xtreme RX850

MOBO
This motherboard has the 3x PCI-e x16's needed, no risers needed unless you want to do the nice open case design.
Also please note, if you buy this on NewEgg soon, you'll get 8GB memory free... taking care of the RAM cost

CPU:
Just need a cheap CPU. Just depends on if you want to use this PC for anything else. Anything from this list will work in the motherboard above:

RAM
If you buy the Mobo above, you'll get 8GB free
Otherwise if you miss the deal, buy this: GSKILL Ripjaw 8GB

CASE:
You'll have to decide for yourself. I personally believe the open homemade case is the best, because of airflow. But if you want a manufactured case, just goto the Case section of NewEgg and find a case that will fix a full ATX Motherboard. A Mid-tower or larger would be suggested, anything smaller you will have airflow/heating issues.

HDD:
Up to you! Find a cheap hard drive, or some people use flash memory to boot into a linux build for mining since the rig is only for that. But if you want to use it for browsing, gaming, music, etc alongside mining - you'll want a Hard drive.

MISC:
- You will need risers to put this into an "open case". You can find the powered risers here at Cablesaurus.
- You also have to consider what OS you'll be running as well. Up to you on that one
- Don't forget a CD-Rom drive if you need to load an OS that way.

And again, this is by no means a "cheap" system, but it will hash LTC at about 1.5M/h, which in the current difficulty will get you about 15 coins a day which works out to $12/day, or $348/month. That is NOT counting power costs.

Hope this helps Battmann! I'm off to bed. Peace!

NOTE: And if any other experienced miners think this information is crap, that's fine. I'm open to correction since I'm new at building "Mining Rigs". I welcome the constructive criticism so I can learn more.

For both. Just for the entertainment and fun of the whole thing, and for the possibility of making my money back on the venture. Then if I want to switch over to LTC for some profit of some sort (if available) then cool beans.

I'm a moron, but I'll ask this anyway:

What is the purpose of you mining?  Are you doing it to learn about how cryptocurrencies are mined and get firsthand experience?  Are you doing it to make money?

If it is because of the first reason then continue on with your quest. If it is to make a profit then by the time you get your eq and figure out how to keep it stable then BTC mining will not be profitable.  LTC may be if everybody doesn't switch over to it but just looking at the 5x difficulty increase since last month I doubt it.

Fatty this is exactly what I am looking for, link me up fatty!!

Cryptocoin Newb Here and a moron to boot, but hey I figured I'd share with you some of the valuable information I've learned, and am now acting on to get a great hashrate like you want! I don't know anything about FPGA's, someone else will have to give you advice on that. This is purely GPU mining advice that I've learned and want to pass on.

NOTE: I'm personally focusing on mining LTC, so I've been looking at building the proper rig for that, to get at least 1.5 M/h for scrypt. I asked a few questions on this thread: https://bitcointalksearch.org/topic/best-litecoin-mining-rig-160463 and ended up with a handful of great answers from "tacotime" and  "xorxor" and "bitobsessed". So here is what I am doing, maybe you can follow suit - or at least customize it to meet your needs.

CASE:

A nice open case design that is easy to build if you are willing to spend $100 to get the supplies (NOTE: You will need to purchase PCI-E risers from Cablesaurus to use this build)
Open Frame Case Guide

Or you can just get a standard large computer case that can handle an ATX Motherboard, and leave the side open. But mounting the third card could be tricky since you'll need a PCI-E riser.

If you want to look at what other designs people are using for their crazy mining rigs, another great thread here:
Mining Rigs Thread (from hardcore sexy, to ugly huge machines - but hey, they produce $$)


RIG:

Next is a feasible build for LTC (will hash 1500 KH/s after all is said and done):
- MOBO: A board w/ 3x PCI-e x16 (probably more expensive) -OR- 2x PCI-e x16 and 1x PCI-e x1 (this will be easier to acquire)
- RAM: 8GB
- GPU: 3x Radeon 7950 GPU's (this will require 6x PCI-E connectors from the PSU)
- PSU: 800W+ 80 Certified that has at least 4x PCI-E connectors, the other 2 will come from Molex -> PCI-E connectors that come with your GPU.
- ONE PCI-E x1 > x16 Powered Risers
- (optional) TWO PCI-E x16 > x16 Powered Risers if you go for the full open case design
- Case: Open Frame Custom Build, or an ATX Mid-Tower

Stick all this crap into one of the open cases, and you have a beauty that looks something like this (except with only 3 cards):


You can obviously modify this design with whatever GPU's you want. The 7950's are particularly good at hashing for LTC, I'm not sure about their ability to hash BTC. You may want to look at the Mining Hardware Comparison chart to find a nice high end card that will hash BTC.

If you need links to specific products let me know. I'll just link you to parts from NewEgg.

I have no idea if this is what you were looking for - hope it helps.

~FAT

So I really want to mine. I don't have a box to mine with (only an older iMac), and so my situation is this:

I need to go to a computer store and buy a box and a high end GPU to just mine the shit out of; give me your recommendations. I will send a small amt of BTC to the most helpful person.

I tried to CPU mine litecoin but got about 7.32 kh/s so yeah, not worth shit. I guess what I want is advice on a high end GPU/FPGA that I can spend a bulk of money on to get a great hashrate, buy a cheap box to store the thing in for the sole purpose of letting it sit and solo mine on, any advice?