Help with 7950 Mining Rig ($2k to spend)

[LibertarianPatriot]

Hey all, I know I'm new here and it might be a little rude to ask questions on my first post, but I was wondering if anyone knew a good setup that uses 6 7950 cards on two rigs? I plan to get the GPU, Processor, Memory and Power Supply and make my own case (using extenders and some 4x4s).

Does anyone know a good setup for $2k and under? I know what cards, I need, but I could use some help selecting the RAM, PSU and processor. Any help from BTCF would be very much appreciated.

One last question, as the difficulty ramps up, how quickly will my earnings diminish? 10% each month? 20%?

Thank you for any help you can provide!

[RAK3]

Hello!

I recently purchased my first ever mining rig, having the same thing in mind, as You do

Here is my configuration:

GPU VGA PCIE16 HD7950 3GB GDDR5/GV-R795WF3-3GD GIGA-BYTE

MB AMD 990FX/SB950 SAM3+ATX GA-990FXA-UD3 GIGA-BYTE

MEMORY DIMM 16GB PC14900 DDR3/HYPERX KIT4 KINGSTON

CPU SEMPRON X2 190 SAM3 BOX 45W 2500 SDX190HDGMBOX AMD

PSU Corsair Professional Platinum Series AX1200I with Corsair Link 1200W ATX EPS12V Fully Modular PSU EU Version

This set me back 2000€ - VAT20%.

I currently only have 4 7950 running via PCI-e x1->x16 and x16->x16 raiser cables because the warehouse is out of stock.
I believe that maybe my PSU can handle one more card but I am looking into a cheap PSU to power only the 5th and 6th card.
I hope that the motherboard will recognize all 6 cards!


I am having no problems, mining at 2,6 Mhash/s, with GUIminer scrypt and cgminer. Clocks 1130 / 1360.

Beware before purchasing Gigabyte 7xxx cards!

These cards only recently started coming out from the factory with a locked core voltage!
I am finding myself in a position, where I could've read forums more properly and ordered Windforce cards with unlocked voltages which are a huge advantage in finding the sweet spot to mine LTC.

Can anyone please tell me if my CPU is okay for mining with such a rig?

[Joerii]

I've read many times that CPU's are pretty much irrelevent in a rig. Go for the cheapest one that fits the socket

[RAK3]

So I did. I also heard that You should have the same amount of RAM than VRAM + some for the OS.
Could anyone comment on that? It sure makes sense though 

[meebs]

So I did. I also heard that You should have the same amount of RAM than VRAM + some for the OS.
Could anyone comment on that? It sure makes sense though 

for BTC mining you just need enough for the OS. the miner uses like 30-40mb only.

for LTC mining with reaper, you'd need probably 4-8gb for the system.. as reaper is a PITA that sucks down ram

[rosckopico]

Hello!

I recently purchased my first ever mining rig, having the same thing in mind, as You do

Here is my configuration:

GPU VGA PCIE16 HD7950 3GB GDDR5/GV-R795WF3-3GD GIGA-BYTE

MB AMD 990FX/SB950 SAM3+ATX GA-990FXA-UD3 GIGA-BYTE

MEMORY DIMM 16GB PC14900 DDR3/HYPERX KIT4 KINGSTON

CPU SEMPRON X2 190 SAM3 BOX 45W 2500 SDX190HDGMBOX AMD

PSU Corsair Professional Platinum Series AX1200I with Corsair Link 1200W ATX EPS12V Fully Modular PSU EU Version

This set me back 2000€ - VAT20%.

I currently only have 4 7950 running via PCI-e x1->x16 and x16->x16 raiser cables because the warehouse is out of stock.
I believe that maybe my PSU can handle one more card but I am looking into a cheap PSU to power only the 5th and 6th card.
I hope that the motherboard will recognize all 6 cards!


I am having no problems, mining at 2,6 Mhash/s, with GUIminer scrypt and cgminer. Clocks 1130 / 1360.

Beware before purchasing Gigabyte 7xxx cards!

These cards only recently started coming out from the factory with a locked core voltage!
I am finding myself in a position, where I could've read forums more properly and ordered Windforce cards with unlocked voltages which are a huge advantage in finding the sweet spot to mine LTC.

Can anyone please tell me if my CPU is okay for mining with such a rig?

Hello RAK3 ,

I am going to build a rig almost like yours!

Are you really mining at 2,6 Mhash/s? For how long have you had this setup?

I was thinking on installing 4 7950, but I read you were going to put 6! How does that work? how many does your motherboard support?

Another thing! How much do you spend on electricity? Is it still profitable?

Sorry about all the questions, i am really excited about building my own mining rig!

Cheers!

[Kinetic915]

Can you really comfortably run 6 7950s on 1200w?

[Kinetic915]

Also is the 4th card running fine off a pcie x1 to x16 riser? I am looking into this as well

[MinerLT]

Also is the 4th card running fine off a pcie x1 to x16 riser? I am looking into this as well

ya me too

[seannnyx]

My suffering with the heat ... I have to lower it to 80 %

[talexeh]

If you're planning to build a rig for bitcoin mining, I'm afraid that you're a little too late to the party. GPU mining is not going to be profitable due to all the FPGAs & ASICs that are hogging the hashrates.

I would strongly recommend that you mine litecoin instead. Apart from multiple 7950s & a 1200W PSU, make sure you get the cheapest processor & HDD since they don't play any role in determining the performance of your mining.

[Eljoka]

To be on the safe side, I'd buy a 1000w platinum PSU for each rig (my understanding is that you'll have 3 7950 per rig).

I currently mine with 5 * Gigabyte 7950 (2 in my everyday gaming/mining rig and 3 in my mining rig). These cards are voltage locked to 1.25v, this would allow you to overclock them a lot, but the temperatures will get VERY high if you don't have proper air flow (I doubt even a 20inch fan blowing on them would be enough, as it wasn't for my setup...). What I did instead is flashing the bios from Fx1 to F43. The card is still voltage locked, but at 1.09v, which gives lower temperature and still enough room to overclock (i have mine at 1100 core and 1350 mem).

My mining rig with 3 * 7950 has a Antec HCP-1000w platinum, Celeron g1610, Gigabyte H77 mobo, 4gb kingston ram and a hdd I had laying around. I get 620kh/s from each card for a total of 1860kh/s and the temps hover around 61C and 70C at 85% fan, depending on the card. The rig is in my basement and has a 8inch fan blowing on them.

My other 2 cards are in my everyday rig and even with a lot of fan and air flow, the top one is still overheating if I put it at full pace. So I have the bottom one at 620kh/s and the top one at 330kh/s, cards temps are between 61C and 71C at 85% and 90% fan, depending on the time of day.

It cost me a little under 2k$ to buy all I needed.

I should specify that I am mining Litecoin.