Topic: Got 18x6870 - Need Advice on MOBO/PSU/Risers (Read 3105 times)

That's why we recommended POWERED x1 to x16 risers. They compensate for all that extra power. The PCIe x16 slots provide more than enough power, so a riser won't provide an issue if it isn't powered.

The second you use PCI risers you're doing things that the standards are not made to handle.

They're expecting to be able to pull wattage from the PCI slot.  Combine this with OC'ing and running them 24/7.. it can be dangerous.

Exactly. FIRE FIRE!

That'll work out with all of the hardware he is using as well. Any GPU setup will. If you guys wanted to, you can use cards from various series 7950, 6990, 5870, etc... you just can't use crossfire. Mining code will utilize whatever combination there is

Agreed.  It's good equipment.  I am going to build similar setup with 7950's.

He came here for advice on the hardware he has picked out. He has picked good hardware. This was his research.

Also about the RAM. 4GB for any rig these days is almost a must. 4GB will ensure it stays stable and is just hassle free.

Just wondering why would you order if you haven't researched exactly what components your going to need yet, just seems like a bad decision to me. However, for LTC mining, you don't need too much ram if you use cgminer so just around 2 gb should suffice. Best of luck with your rig!

He is using a dual 750W PSU for better and safer power spread.

Amazon has the Lepa G1600 for $288. Just in case

Lack of experience doesn't mean anything. I assembled my first computer not knowing one iota of how to do it. All I had was an anti-static wristband and that was it. Got it assembled, BIOS programmed, and everything done on my own. OP is perfectly able to build three rigs. I'm sure he will come asking questions when he receives the hardware. Also, who knows if he has built a computer before? He came asking for hardware dedicated to the purpose of mining Bitcoins and Altcoins. I came asking about how >4 GPU rigs even worked, and got multiple answers. This board is a source of help, so we give help. He'll be fine.

I'm implying a fire as a result of OP's lack of experience. Why anyone would start big when they clearly have no clue what they're doing is beyond me.

2 sticks of 2GB of RAM on each rig should be sufficient. Remember to install 64 bit OS of whatever you choose. I recommend Ubuntu or Debian.

And for the add2psu, I wouldn't get it. I'd get what notaek recommended.

And yes, one psu would only power 3 cards.


That would work perfectly.

Or you could use this: http://www.frozencpu.com/products/5637/cpa-167/Lian_Li_Dual_Power_Supply_Adapter_Cable.html

Doesn't matter really, as long as you have some way of powering the second PSU on when you turn the first one on.

Thanks alot!

So i decided to go with ram:
http://www.microcenter.com/product/382074/Ballistix_Sport_4GB_DDR3-1600_(PC3-12800)_CL9_Desktop_Memory_Module_Kit_(Two_2GB_Memory_Modules)

I will be getting 9 QTY 1x to 16x pci e powered risers, and will also order 16x to 16x, but those will take more time to arrive.

So the bottom line for add2psu - do i need it or no? I understand that one of the psu would be just power the other 3 cards, nothing else?

Thanks

No fire. I've seen massive GPU farms that run more than 12 rigs at once. Just google mining rigs and hold your eyes in. People make some insane stuff man. 3 rigs is nothing

Here comes a fire 

Thank you for clarifying the ADD2PSU purpose. And he is correct, I forgot to mention the power supply allocation for the risers. Make sure each card is connected to the same PSU, don't crosswire the cards between PSUs.

The benefit of ADD2PSU is making sure your chained PSUs start simultaneously, or as close to it as possible. Otherwise, you may run into problems if some of your cards aren't getting power when the motherboard is POSTing, so they don't get detected.

Also, make sure the molex cable and PCI-E power cables for a card on a powered riser all comes from the same PSU. Again, this can be a source of trouble if you mix the sources.

Grim, jimmy3dilta, Jama, Marrs, notaek, Cryptocables - Thanks for the advice! It was really helpful. I have spent some time and 'built' a rig which i would think(hope) it would support 6 GPUS?  Do you think it will work?

Mobo:
3x http://microcenter.com/product/401768/Z77A-G45_Socket_1155_ATX_Motherboard

CPU:
3x http://microcenter.com/product/408967/Celeron_G1610_26GHz_LGA_1155_Boxed_Processor

RAM:
1.5x http://microcenter.com/product/401550/Hyper_X_Red_8GB_DDR3-1600_(PC3-12800)_CL_9_Desktop_Memory_Kit_(Two_4GB_Memory_Modules)

( I would use 4GB per rig)

PSU:
Option #1: 6x http://www.microcenter.com/product/404598/SuperNOVA_NEX750B_750_Watt_ATX_12V_Power_Supply


GPU(already being shipped):
18x http://www.newegg.com/Product/Product.aspx?Item=N82E16814202032


PCI E Extenders:
9x Powered ones: http://www.cryptocables.com/
9x Non powered ones: from ebay.

-------


1) Will my MOBO handle 6 GPUS? Anyone has this particular board? or at least something close to it? Would you recommend it?
2) Do i really need CPU for LTC mining? will this celeron work?
3) 4GB ram per rig should be plenty?
4) I would use 2 PSU's per rig - will that work?, UNLESS YOU KNOW A BETTER(CHEAPER) ALTERNATIVE?
4.1) Do I need ADD2PSU to connect those two PSU's? http://www.add2psu.com/store/
5) will 3 powered extenders per board is  enough?
5.1) Should i get powered 1x extenders or 16x(powered)?

Thank yous

I have a lot of powered risers/extenders for a good price if you happen to be looking for any. PM me if you have any questions! <3

Mobo:

MSI 990FXA-GD80

cheaper alternative without a power-on switch is the:

MSI 990FXA-GD65

Note: There is also a V2 verson of each mobo which simply gurantees a bios ready for Vishera CPUs.


CPU + Ram:

Sempron + 1x 4 GB


PSU:

2x XFX Core Edition PRO 750W
(4x PCI-E)

One 6 pin PCI-e connector and 1 of the 2xmolex to 1x6 pin adapters on each card with this PSU and you should be fine.

Note: Use add2psu adapters or even cheaper the paperclip method!
Note: PSU2 needs to be switched on before PSU1.
Note: The internals of this PSU is a Seasonic single 12v Rail = very good.


Extenders:

Use the bottom last slot of the mobo to plug in 1 GPU.
Use 3 non powered extenders and 2 powered ones.
Alternative: Use 4 non powered extenders and 2 powered ones.
Note: The powered extenders ALWAYS need their power from the PSU1 = the one plugged into your mobo!
Note: 1x to 16x also work for 16x slots.

For the motherboard and CPU give a look to some good-chipset-with-few-features motherboards. I presume that you are going to mine some LTC, so the CPU will have his part in this work.

You need (imho):
- 6 Pci Express slots (you will need the powered risers too)
- Fanless chipset cooling (unless you want to stop the rig once a year, cleaning dust under that tiny fins)
- H77 chipset (you don't need to overclock the CPU, so forget the Z77). I'd skip the H68 because they are not born for the latest Ivy Bridge processors (lower power usage and heat)
- a good Ivy Bridge processor, just a baseline i5 can be sufficient. Ivy Bridge (32nm)
- huge overclock cpu cooler, with horizontal (parallel to the motherboard) fan. This helps alot to keep cool the CPU area (chipset, memory, capacitors, etc) and let your motherboard last (way) longer
- two good memory sticks (buy a dual channel kit with an heat-spreader on them)
- not much to say about the storage (where you install the operative system) I'm using a Velociraptor just because it was hanging here (most people uses USB sticks it seems)

Source: right now I'm mining on a 2005 Asus A8N-SLI Premium motherboard, with an AMD Opteron CPU on it and the very same Samsung TCCD rams I've had 8 years ago. And a very good PSU (Enermax Liberty) with "modular" cables, that allow air to bass by without unused plugs hanging around

How technically competent are you with regards to soldering etc.
As I have a solution which will slash your PSU cost by a huge factor.

It involves powering your cards by server psus which only give 12v and just using a very low power (about 300w) to power the motherboard.
It requires you to make a custom loom and use all powered risers (which you can make your self)

I have gone this way, and have only spent £70 on 5KW worth of PSU which the normal way would have run well over £500

No. Buy two less expensive (but still high quality) psus and chain them with an add2psu.

Probably it's one of the most important components, and very often they costs as much as a good video-card. Keeping a PSU on its limit can lower the stability of your system, give lower alimentation quality (hence lower frequencies you can reach in overclock, or higher stable volts), higher failure probability (stopping entirely your rig) and probably higher power usage, caused by a lower efficiency.

The card TDP is 150W, a good indicator of its power needs, and according to this link https://en.bitcoin.it/wiki/Mining_hardware_comparison I wouldn't go below a 1000 watt. Probably the best solution is a Quad-Sli (or quad-crossfire) certified PSU, also because they have enough 6pin connectors and you don't need too many adapters.

Do some research, very often the "overclock branded" PSUs are white-label from OEM makers (i.e. Fortron), and you pay more just for the service, not the product quality itself.

do i really need to expensive psu? how much each card pulls?

Whaaaat how did you get an order in???

As far as your questions, 4gb of ram should be fine.  I have 6950's and they use 500mbs each.  That x 6 = 3gb which should give you a little left over for your operating system.

If you want to stick to one PSU, your looking at something like this: http://www.newegg.com/Product/Product.aspx?Item=N82E16817494006 
They actually have it on Bitcoinstore for a little cheaper + free shipping.  Just note that you will need to use 2 molex to 6pin adapters, because that psu only has 10 pcie connectors. 

Motherboards, there are threads on here discussing good mining mobos+mobos that can hold 6 cards.  You might be able to find some good stuff in there.

Hi,

I just placed an order for 18x 6870. Those should arrive early next week.

I would like someone to give me advise on what MOBO's should i get? I would like to keep it in 3 rigs (6 cards each(preferably)). What about PSU? Also RAM? how much ram do i need for LTC mining?

More importantly psi x extenders, which ones should i get? how many powered extenders?

Also, can i use 1x to 16x extender on 16x slot? or does it have to be 16x to 16x?

Any information would be really helpful.

I will send few LTC if your post is helpful, I might need to split the coins for multiple people.

Thanks alot!