Topic: Got 18x6870 - Need Advice on MOBO/PSU/Risers - page 2. (Read 3066 times)

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!