Topic: Another newbie mining rig post (Read 2235 times)

well, that was a shitty psu (http://www.dixcomputers.com/computer-parts/power-supplies/inter-tech-energon-eps-750w-atx-psu-750w.html?SID=25a78d4aceb73d5fe83fccad270e389b) indeed, but not everybody can afford Corsair,Antec or Thermaltake.
Here's a Power Supply Calculator: http://extreme.outervision.com/psucalculatorlite.jsp
Hope it will help op buy the right psu. Cheers!

The 6990's are very power hungry. Even with 1200w PSU i would have thought it would be a struggle to add a fourth card, that is of course assuming you even manage to get one in there.

Also heat, I would say that rig would only be good for 2 6990's. Cramming them together in my experience does not work as the coolers simply cannot dissipate that much heat when 3 of them are crammed next to each other. If you're buying some PCI-E risers to have the cards away from the motherboard then maybe it's viable.

Think carefully about why you're buying this rig with your friends too, for profit? Unlikely you'll make a single dollar back on the total investment
You were getting the parts anyway and want to make some money back on them? A better scenario, but then you need to think about who gets the parts when it becomes unprofitable, and splitting the costs of various things.

Where are you planning on having this rig? In a bedroom, no way. The fans will drive you crazy. Even if it's in an adjacent room the noise can be pretty annoying.


As for gaming while mining, you will damn near have to stop all mining activity while you want to game, as it will make playing the game an unenjoyably experience.

Whaaat? What kind of wimpy PSU were u using? Like a previous poster I too am currently running two 5870 cards running off of a 600 Watt PSU. Total system power draw is 434 Watts!

PSU is a Thermaltake ToughPower 600W
Second PSU is a Corsair EliteXStream 1000W which will run two 5870s once again (I got it hoping that I can still find a 5970 but no luck with that).

So yeah try to get the best quality PSU you can and also pay close attention to its efficiency rating (80 Plus and up is the minimum acceptable level)

Yeah... for me personally, 80+ Gold with enough amperage on each 12v rail (if more than one) and i have a overkill habit of getting psu's with almost double wattage than i need, for the sake of heat and sound (1000w using 500w more efficient than 550w using 500w)

But, for the sake of "will this psu run these cards" people should at least learn the basics of what their 12v rails can supply and what each card needs. 3 12v rails at 15a, neither one of those rails will support a 30a card very well.

And let's not forget about efficiency, personally i'd never buy anything below 80+ bronze and I almost consider 80+ silver a minimum for when you are going to run something 24/7 and electricity cost actually matters, unless you have free power

This ^
Quality of power supply is much more important than overall wattage rating.

Next time use a quality psu, currently i have 2x 5850s and 5870 running at 940/300 for the 50s and 950/300 for the 70, granted on stock voltage for the cards but the entire rig still pulls just shy of 500w from the wall.

1. not sure about the 4 gpu limit in Windows (I think Windows actually supports up to 8 gpu's, the 4 gpu limit might be just for crossfire), but if you want to use the machine while mining, you can just set the miners on your primary video card (the one your monitor is hooked up to) to lower aggression. That will reduce the gui lag and at low enough aggression even allow you to do some gaming (though that will reduce your hashrate on that video card - some from lower aggression, some from utilizing the gpu for game rendering).
There is one issue though - for mining on the 6990's you will have to run the 2.4 version of AMD SDK. Under Windows, that will utilize 100% of a cpu core per miner (gpu). With two 6990's, that will means 100% utilization of a 4-core cpu. That will increase power consumption and reduce the machine's responsiveness. This doesn't occur under linux.

2. a 6990 under load uses some 300-350W. With overclocking that can reach 400W. Add some 200W for the rest of the system, less if you build a dedicated mining rig. For 3 6990's, you'll need at least a 1200W psu, more if you plan to overclock.

3.1. yes, removing >1kW of heat from a case is a MAJOR issue. Just removing the side panels on the case will not do, you will also have to ensure very good airflow through the case (like several high-airflow case fans). You will still probably have to run the fans on the 6990's at max or near-max rpm, and they are really LOUD. As in, three of them will sound pretty much like a vacuum cleaner.
3.2. Make sure the pci-express slots on your motherboard are spaced far enough apart to allow installation of dual-slot video cards. Even then you will probably have to use spacers between the cards to ensure enough separation for adequate airflow.
3.3. There are motherboards that can accommodate 4 dual-slot video cards. In that case you can theoretically add another 6990, but that will further increase problems with heat, noise and power requirements.

5. don't even think about running a rig with >1kW of power consumption in a room without air conditioning

Thanks gents,
That was all kinds of useful
Any further advice will also be greatly appreciated.

As above Windows only supports 4 GPUs. If I were you I'd consider a mining only rig with 2 cards (crappy CPU / RAM are OK) and drop a single card into your regular / gaming PC. I assume if you're gaming you're using Windows so also saves some work learning Linux unless you know both. Mining at lower aggression along with other normal tasks and games works fine (albeit more slowly), so that way you can use your main PC as normal and max out the other one for mining only. Also means you can get away with some cheaper PSUs and are less likely to have cooling / mounting problems.

wrong.

I'm running two PCs. One of them has a 5870 and a 5850. The other one has two (2) 5850s. All overclocked. The total max wattage added from both PCs pull 850W from the wall. I'm using a 650W power supply for each PC. I could probably get away with using a 500W if I wanted to.

With 3x 6990 you would have to use linux.
windows only suports 4 GPU's

6990 needs more than 150 W, more like 250 w in idle, and 350 w in full load.
here's an example:http://images.hardwarecanucks.com/image//skymtl/GPU/HD6990/HD6990-72.jpg

I've had a 5870 and a 5850 with one 750 w power supply and the psu could not keep up with the power consumption, so I guess you would need a psu bigger than 1000 W.

Hey guys,

Me and a friend are building a rig, 6990x3, pretty much as listed on the wiki mining rigs page. ( https://en.bitcoin.it/wiki/Mining_rig#Three_ATI_6990s,_Approximately_2.1_Ghash/s )

1. I have a home office and would like to use some basic spreadsheets and at least play some SC2 and some Mass Effect (1/2/3) on it. How does that affect mining? I've read a post on multitasking (gaming) while mining but I'm not clear on whether the GPGPU ceases to function completely or if it just slows down.

2. Also I'm not clear on how much power is required. It seems like 150W for the PC + components and 150W per 6990. So about 600W. In your experience is this enough?

3. How do 3 cards behave in one machine?
3.1 Are there MAJOR cooling issues or does leaving the case open solve the problem?
3.2 Are there space issues?
3.3 Can another card fit? (another friends wants to know if he can come in on the action and add a 4th 6990)

4. Form what I've read, Windows and Linux perform pretty much on par so there is no big reason to choose Linux over Windows, is this accurate?

5. Are there any major unforeseens that experience has taught you with this kind of rig?

Thanks