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Topic: Build me a LTC rig (Read 3578 times)

newbie
Activity: 28
Merit: 0
May 26, 2013, 12:10:29 AM
#47
All my 7950's happy sit at 650.  One of them gets 680-690.  You just need to find your cards g-spot.
newbie
Activity: 14
Merit: 0
May 25, 2013, 11:04:02 PM
#46
the only thing I object to is the 7950, I have 2 and all I can think of is that I am losing 200 K/Hs than if I had 7970s, and I just ordered 2 from Amazon last night and they showed up at my door this morning before I woke up. I was impressed.
full member
Activity: 170
Merit: 100
May 25, 2013, 04:01:41 PM
#44
is there a special cable or adapter i need for the power supply to reach all 4 cards?
link?
Not if you buy the Seasonic 1250W gold 80+ it's modular(cables plug into PSU and components so you dont have a lot of clutter. The PSU comes with straps to organize the wires as well. Very good setup in the PSU box. Best PSU out IMO.

perfect thanks Smiley
full member
Activity: 182
Merit: 100
fml
May 25, 2013, 03:04:30 PM
#43
The Milk Crate route with a tiny twist.. just set the cards at a 45 degree angle to help cooling and put a 15$ box fan on the top. Cards stay about 75 C or less.

Also powered with two 750w PS as that is cheaper than one 1200w PS.. using the add2psu.com module.

Also this draws ~1200 watts at the wall, and does ~2.4Mh/s. I can probably improve this some, just have not had the time.



That is a cool looking rig, but aren't you kind of adding 2 points of failure?
hero member
Activity: 798
Merit: 531
Crypto is King.
May 25, 2013, 02:34:13 PM
#42
is there a special cable or adapter i need for the power supply to reach all 4 cards?
link?
Not if you buy the Seasonic 1250W gold 80+ it's modular(cables plug into PSU and components so you dont have a lot of clutter. The PSU comes with straps to organize the wires as well. Very good setup in the PSU box. Best PSU out IMO.
full member
Activity: 170
Merit: 100
May 24, 2013, 09:48:07 PM
#41
is there a special cable or adapter i need for the power supply to reach all 4 cards?
link?
full member
Activity: 126
Merit: 100
May 24, 2013, 05:30:21 PM
#40
The Milk Crate route with a tiny twist.. just set the cards at a 45 degree angle to help cooling and put a 15$ box fan on the top. Cards stay about 75 C or less.

Also powered with two 750w PS as that is cheaper than one 1200w PS.. using the add2psu.com module.

Also this draws ~1200 watts at the wall, and does ~2.4Mh/s. I can probably improve this some, just have not had the time.



this add2psu.com module sounds interesting - i made a mistake of getting 2 psus to power 4 cards in a single rig and eventually split them up into 2 rigs when i couldn't get it to work - i never factored in that each card can draw upto 75W from the mobo  - i'm assuming using 2 psus with this adapter worked out for you. any issues? would you recommend it?
full member
Activity: 126
Merit: 100
May 24, 2013, 05:26:27 PM
#39
Does it make much sense to build a dedicated GPU rig at this point in time?  I calculated a simple payoff of 5 months (which sounds good) for a rig that I'd build, but with BTC difficulty increasing at 10%/week it looks like it might never pay itself off.

Thoughts?

Also while I am posting, is a 650W gold PS enough to power a rig with 2 7950's?  (my current 7950 appears to draw ~200W).  I think the extra 200W should be enough to power the rest of the PC components...

Yes I have 2 rigs exactly like this. 650W + 2 x Sapphire 7950s but no hard drive just USB boot. Powertune at +20 and they are very, stable each rig doing 1250 kh/s for LTC mining. Should be even less power draw for BTC mining.
mnx
newbie
Activity: 51
Merit: 0
May 24, 2013, 09:51:53 AM
#38
I was using BTC to calculate the worst case scenario.  Of course I will mine whatever is most profitable.  I began mining BTC/altcoins with a 7950 on April 9th and have just reached b/e on my investment.  I don't expect the payoff to be nearly as quick next time...

member
Activity: 74
Merit: 10
May 24, 2013, 09:36:55 AM
#37
Does it make much sense to build a dedicated GPU rig at this point in time?  I calculated a simple payoff of 5 months (which sounds good) for a rig that I'd build, but with BTC difficulty increasing at 10%/week it looks like it might never pay itself off.

Thoughts?

Also while I am posting, is a 650W gold PS enough to power a rig with 2 7950's?  (my current 7950 appears to draw ~200W).  I think the extra 200W should be enough to power the rest of the PC components...

7950s atleast in my experience pull about 300W each.. so it would be close with 2 7950s + CPU and HD.. might be ok if you went the linux route and used a USB to boot.

BTW i would not mine BTC, just will never keep up with the FPGs or ASIC miners. Mine LTC/or some other scrypt, then convert it to BTC.

I started with 4 rigs of 2 GPUs in each. Spent $4000 on the whole setup. 1st month made $1700, 2nd month I am working towards a goal of about $1500. So I project the 3rd month I will start making money on this project of mine.
mnx
newbie
Activity: 51
Merit: 0
May 24, 2013, 08:59:21 AM
#36
Does it make much sense to build a dedicated GPU rig at this point in time?  I calculated a simple payoff of 5 months (which sounds good) for a rig that I'd build, but with BTC difficulty increasing at 10%/week it looks like it might never pay itself off.

Thoughts?

Also while I am posting, is a 650W gold PS enough to power a rig with 2 7950's?  (my current 7950 appears to draw ~200W).  I think the extra 200W should be enough to power the rest of the PC components...
member
Activity: 74
Merit: 10
May 24, 2013, 08:43:37 AM
#35
The Milk Crate route with a tiny twist.. just set the cards at a 45 degree angle to help cooling and put a 15$ box fan on the top. Cards stay about 75 C or less.

Also powered with two 750w PS as that is cheaper than one 1200w PS.. using the add2psu.com module.

Also this draws ~1200 watts at the wall, and does ~2.4Mh/s. I can probably improve this some, just have not had the time.

member
Activity: 115
Merit: 10
May 24, 2013, 08:34:42 AM
#34
I have 3 Sapphire 7970 OC running stable at 720Kh/s, total rig draw only 750W at the wall!

Was looking into 7950 since everyone is raving about it, but now that I see they only get 630-650Kh/s and drawing 730W, plus someone mentioned horrible vacuum noise level (I live in apartment too without a garage or basement), 7970 seems to be the best bet!
full member
Activity: 182
Merit: 100
fml
May 23, 2013, 08:46:13 PM
#33
http://www.reddit.com/r/litecoinmining/comments/1ddhie/undervolt_overclock_and_cgminer_settings_for_2x/

There's 1 guy here, who is running 3x7950's, undervolted, and is drawing 730W from the wall, which would encompass the entire rig.

I've seen many posts, on this forum, and others, with problems getting the full hashing power, from a 7970. They are finnicky. From what I can tell, 7950's are the prefered card for mining. But it's all personal preference, and depends on things like, how much $$ you have to spend.

I only have 7950's, so, I can't speak from experience, as to which is actually better, just refering to data I've collected.

https://bitcointalksearch.org/topic/ltc-why-are-you-mining-with-7950-and-not-with-7970-203946

Now, some people also say that 7970's have a higher resale value, which is true, up to a point. Once the next gen cards come out, the resale value of all 7xxxx cards plumment. When I tried to sell my 5870, after buying my first 7950, I had a hell of a time.
hero member
Activity: 518
Merit: 500
May 23, 2013, 08:27:53 PM
#32
You can undervolt a 7950, still get ~650 KH/Sec, at 40-50W less, bringing it down to ~150W per card.

As I said can you back this up with data rather than throwing random numbers in the air? How did you get to the values of 40~50W and the 150W per card? Also suddenly 650 kh/s?

Also one can undervolt a 7970 too :/

Quote
Also, the initial investment is ~$400 more, for 4 7970's.

To get the same hashing power out of 7950's, you're eventually going to need more motherboards, processors, RAM, etc. Also, even though the investment is greater, the return of investment stays the same period as you have a higher hashing power. The 7970 is 21% faster, and the investment is 25% larger. These numbers are in the same ballpark and therefore I still do not see why one would not buy the most hashing power per motherboard :/
full member
Activity: 182
Merit: 100
fml
May 23, 2013, 08:25:49 PM
#31
any suggestions on best 7950?
if you can afford 7950, then you should jus go h.a.m, get the 7970s, sapphire twin x oc edition, then a 1500 watt power supply gold certified. you dont need a really powerful cpu, but i'd suggest the 22nm i5 and minimum of 8gb ram, if you use reaper, get 16gb. you may want to use a custom case or crate for your build. to allow the hardware space and additional cooling. pcie risers are a good option, get powered ones. i use a ssd, i dont know if that improves performance.

7950's prove to be more profitable. The extra electricity, plus the extra $100 per card, is not worth the little bit of extra hashing power. Not only that, 7970's are notoriously harder to get the settings right. I have the 3 fan Gigabyte 7950, and I get 620 KH/sec, at stock speeds.

That mobo you picked, that's only got 2X PCIE16 slots, is that enough? I've also read in places too, that 3 GPU's per board is better, for cooling purposes, and, so you don't have to fuck around with powered riser cables.

Also, I read that 8 GB Ram should be plenty

Can you please back this up with data?

The data I have is that I draw 1243W from the socket with 4x 7970 @ 750kh/s - significantly faster than 7950. With 90% PSU efficiency, this means 1118W at the PSU side --> minus ~160W for processor, motherboard, HDD and peripherals, 958 W for just the cards --> 239W per card.

Now, I hear the 7950's draw about 200W per card (can you confirm?), at 620 KH/s

So, this means:

7950 ---> 620/200 = ~ 3.1 kh/W
7970 ---> 750/239 = ~ 3.14 kh/W

And this makes sense as it's practically the same board, but at higher clocks. So as the output per watt is practically the same (give or take 5% in my assumptions), I see no reason why not to put the top cards in your system :/

You can undervolt a 7950, still get ~650 KH/Sec, at 40-50W less, bringing it down to ~150W per card.
Also, the initial investment is ~$400 more, for 4 7970's.
hero member
Activity: 518
Merit: 500
May 23, 2013, 08:22:51 PM
#30
any suggestions on best 7950?
if you can afford 7950, then you should jus go h.a.m, get the 7970s, sapphire twin x oc edition, then a 1500 watt power supply gold certified. you dont need a really powerful cpu, but i'd suggest the 22nm i5 and minimum of 8gb ram, if you use reaper, get 16gb. you may want to use a custom case or crate for your build. to allow the hardware space and additional cooling. pcie risers are a good option, get powered ones. i use a ssd, i dont know if that improves performance.

7950's prove to be more profitable. The extra electricity, plus the extra $100 per card, is not worth the little bit of extra hashing power. Not only that, 7970's are notoriously harder to get the settings right. I have the 3 fan Gigabyte 7950, and I get 620 KH/sec, at stock speeds.

That mobo you picked, that's only got 2X PCIE16 slots, is that enough? I've also read in places too, that 3 GPU's per board is better, for cooling purposes, and, so you don't have to fuck around with powered riser cables.

Also, I read that 8 GB Ram should be plenty

Can you please back this up with data?

The data I have is that I draw 1243W from the socket with 4x 7970 @ 750kh/s - significantly faster than 7950. With 90% PSU efficiency, this means 1118W at the PSU side --> minus ~160W for processor, motherboard, HDD and peripherals, 958 W for just the cards --> 239W per card. The 160 was based on the fact that the idle system draws 220W, and data suggests the 7970's use 15W per card @ idle.

Now, I hear the 7950's draw about 200W per card (can you confirm?), at 620 KH/s

So, this means:

7950 ---> 620/200 = ~ 3.1 kh/W
7970 ---> 750/239 = ~ 3.14 kh/W

And this makes sense as it's practically the same board, but at higher clocks. So as the output per watt is practically the same (give or take 5% in my assumptions), I see no reason why not to put the top cards in your system :/
full member
Activity: 182
Merit: 100
fml
May 23, 2013, 07:57:48 PM
#29
any suggestions on best 7950?
if you can afford 7950, then you should jus go h.a.m, get the 7970s, sapphire twin x oc edition, then a 1500 watt power supply gold certified. you dont need a really powerful cpu, but i'd suggest the 22nm i5 and minimum of 8gb ram, if you use reaper, get 16gb. you may want to use a custom case or crate for your build. to allow the hardware space and additional cooling. pcie risers are a good option, get powered ones. i use a ssd, i dont know if that improves performance.

7950's prove to be more profitable. The extra electricity, plus the extra $100 per card, is not worth the little bit of extra hashing power. Not only that, 7970's are notoriously harder to get the settings right. I have the 3 fan Gigabyte 7950, and I get 620 KH/sec, at stock speeds.

That mobo you picked, that's only got 2X PCIE16 slots, is that enough? I've also read in places too, that 3 GPU's per board is better, for cooling purposes, and, so you don't have to fuck around with powered riser cables.

Also, I read that 8 GB Ram should be plenty

thanks that was helpful

what motherboard you recommend then?

Further research indicated that that board is the best for mining right now, it's the 1X16, and 16X16 powered riser cables, make the difference. 4 GPU's are better. I'm also in the process of designing a rig. I found this website very helpful;

[link] http://www.coinminingrigs.com/ [/link]
full member
Activity: 170
Merit: 100
May 23, 2013, 07:51:58 PM
#28
any suggestions on best 7950?
if you can afford 7950, then you should jus go h.a.m, get the 7970s, sapphire twin x oc edition, then a 1500 watt power supply gold certified. you dont need a really powerful cpu, but i'd suggest the 22nm i5 and minimum of 8gb ram, if you use reaper, get 16gb. you may want to use a custom case or crate for your build. to allow the hardware space and additional cooling. pcie risers are a good option, get powered ones. i use a ssd, i dont know if that improves performance.

7950's prove to be more profitable. The extra electricity, plus the extra $100 per card, is not worth the little bit of extra hashing power. Not only that, 7970's are notoriously harder to get the settings right. I have the 3 fan Gigabyte 7950, and I get 620 KH/sec, at stock speeds.

That mobo you picked, that's only got 2X PCIE16 slots, is that enough? I've also read in places too, that 3 GPU's per board is better, for cooling purposes, and, so you don't have to fuck around with powered riser cables.

Also, I read that 8 GB Ram should be plenty

thanks that was helpful

what motherboard you recommend then?
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