Bitcoin Forum

I'm consdering building a litecoin mining rig.  I know that you can use 1x to 16x PCI-E extenders for BTC mining rigs but I also know that LTC is more intensive on GPUs, so I'm wondering if a 1x to 16x extender will decrease perfomance.

Also, do you need a decently powered CPU for a litecoin rig?  Will the cheapest Celeron or cheapest single-core Sempron work?

Any advice is appreciated... thanks!

P.S. Sorry if this is the wrong forum or if these questions are answered elsewhere.  I tried a quick search and didn't find anything.

no noticeable performance decrease unless your rig is underpowered. no need to worry about the cpu, cheapest is fine, youll be using the gpu.

the 1x to 16x PCI-E extenders work perfectly fine for LTC rigs.  I have numerous rigs running with numerous of those adapters, and no problems.  The cards on 16x -> 16x do not get higher performance than the cards on 1x -> 16x.

Also you only need the cheapest CPU.  (Still go for 64-bit though, in case you're thinking about a really old processor that is only 32-bit).  Other than that the CPU is irrelevant.

You might want to throw in more RAM on a LTC rig than a BTC rig, but if you're using cgminer, that isn't critical either.  

Yup spend the money on the GPU and the extra 100 for a rock solid PSU. Go with PCpower and cooling, or heck corsair and seasonic.... just because it say 1100w on the sticker dont mean its high quality.

Edit, you can go even with an older gen sckt 775 chip/mobo and get em dirt cheap. Toss in a small HD to load the OS and your gold.

Also, try to make it a single rail PSU.  Not as critical as some people would have you believe, but if it is a multi rail PSU you have to pay attention to how you balance your loads.  I overloaded a rail one time on a multi-rail PSU and the thing died really quick.  Luckily no other hardware was damaged. 

Thanks for the advice everyone!

Do you recommend an AMD or Intel motherboard/CPU?

Also do you think it's a better idea to get a CPU/mobo with integrated graphics, or is it okay to use one of the mining GPUs for video? (this would be a dedicated mining rig... it would just be sitting there with a terminal running cgminer)

Ty again!

I've never used a mobo with integrated graphics for mining, but I have heard quite a few people say that can cause problems.  I use one of the mining GPUs as video when I need it.  There's no problem in doing so.  That card may run just a few degrees hotter than the others on the rig I've noticed though. 

I've used both AMD and Intel.  Haven't had an issue with either, so not sure one is better than the other.  It may just be whatever the best deal you can get is. 

amd is cheapest. you can get a sempron and mobo with support of 4 gpus for around 130 combined on newegg. add ram (i suggest at least 2gb per GPU for ltc), PSU, and a usb drive and you have an open air mining rig for <$300 before the gpus.

Sounds great... now one more question; do you need powered 1x to 16x risers?
I have a bitcoin rig with 2 unpowered 1x to 16x risers for 5830s and they run fine but I see some people saying you need powered risers.

It depends on how many gpus you are running and what gpus they are really.  I've ran 4 just fine on no powered risers, but then I tried running 5, and melted the mobo.  If 3 or less I would say no.  If 4 then the answer is probably just to be safe.  You might be living dangerously if you don't have atleast one powered riser.  If 5 then I would say it is a requirement.

To clarify; is that 4+ GPUs on unpowered extenders, or 4+ GPUs total?
I was considering doing 4x 7950 on a motherboard with at least 2 16x slots, so I'd only need 2 1x risers.

I was also considering using this board with a Sempron 145: http://www.amazon.com/gp/product/B0055QYKQO/
With that board I wouldn't need to worry about 1x risers

You're probably fine not using any powered risers on that board using 4 GPUS total. 

Wait for someone else's confirmation of that though.  I'm running a couple of 4 GPU rigs with no powered risers, and not having any trouble.  I just hate to tell you, you're fine, and then have your mobo melt. 

Alright, sounds good.  I'm going to do some more research and probably end up getting a board with only 0-2 1x slots that I need to run cards on.  It seems like powered risers are somewhat hard to come by and I'd rather not deal with making my own.

Either way I really appreciate the advice; thanks again!
I'll post here to warn you & others if anything I try blows up. :p

Burn that shit to the ground.  Go LTC. 

Hahaha well my plan is to build one rig and get a feel for ltc mining, work out the kinks in the system, etc., and then see if anyone is interested in investing in a small hosted mining setup and ideally building a few more rigs and hosting them for a small fee. Not going to be a huge operation due to the power limitations of the house I live in and also because I don't really have much rep on these forums, but a good starting place especially with the craziness going on in the btc mining world right now.

But of course I still need to actually build my first ltc rig. So yeah, I'll hopefully be burning that shit to the ground in a week or so. :P

This is from memory so it's probably wrong.
x16 spec is 75 watts
x1 spec is 25 watts

You run the risk of pulling too much current through the 25 watt connector, which results in problems under several possible conditions:

1) The GPU prefers PCI power over 6+2pin connector power
2) The PSU or MoBo cannot handle the full load from the PCI-E connectors combined, when over-loaded
3) The x1 connector's traces were slimmed down to only support 25 Watts

There's also this mobo which comes with a 12 V molex right by the slot for extra power:
www.newegg.com/Product/Product.aspx?Item=N82E16813157339

The asrock boards have nice power/reset buttons built into them (most of them) which is nice if you're going caseless and don't wanna bring out the screwdriver and start jabbing pins on the header.

Hi,

Not sure if this helps but I have my first rig, it is an old ex corporate machine with a AMD 64 3500 cpu (v.slow), however the mobo has 2 pci e slots. A 1x slot and a 16x slot, due to space I will be using both on risers, atm I just have a 7850 in and that is running off the 1x and I am pulling 350kh/s (btw I have a cool master 650 watt 80% rated PSU and I have pulled out the original 280watt).

I am just waiting on my second card now which will be making it's way into use next week.

The only big issue I have is placement of the cards. Luckily I have access to a 3D printer so once the 2nd card comes I will be measuring up both cards to make something stable but airy.

I would definitely go for powered.

Here a link to a post I made where I caught my mobo on fire:

https://bitcointalk.org/index.php?topic=161242.0
TLDR : The likely cause seemed to be unpowered risers and incorrect cgminer settings.

That being said I do still have that rig running the 4 cards without powered risers without further issue.  I just got lazy and left cgminer at the original settings I tried.

So basically:
1. I'm fine with unpowered if I'm plugging into full sized connectors (16x, 8x, 4x)
Or
2. If there's a separate molex connector for the 1x slots
But if not, I need a powered riser?
(Is the above all correct?)

I have a friend who set up a ltc rig with unpowered connectors and we were getting all kinds of cgminer errors with ltc but not with btc... this might explain the mystery.

This is all very useful info; I think I'm going to try an asrock board with either enough full-sized slots or with the extra molex connectors based on all the info above.

For my latest build I picked up an AMD APU to power the monitor instead of off the gpu or integrated graphics. $43 for the APU, just needs to be set as default display in BIOS. The only problem with this is you are more limited with the mobos available, most only have 2 pci x16 because of the APU slot, but mine also has 3 PCI x1 slots.

Best mobo for APU is ASRock A55DEL (http://www.idealo.co.uk/compare/3331649/asrock-a55del.html) 5 x PCI-E for under $70


And btw You don't have to use powered risers even for 6 GPUs if your mobo has power port next to PCI-E (6PIN usually. I have MSI 990FXA-GD65 with 6 GPUs, no problems at all.

http://pl.msi.com/pic/product/five_pictures1_2401_20110531112823.jpg

I will going up to 5 cards on my Gigabyte 990fx-UD5 (it doesn't have a 6pin connector like that MSI board, *nifty*)

I've read that 6 pin connectors will supply 75w while the 6+2 pin connectors will supply125w for a total of 225 watts to the card. I'm using gigabyte 9750's.. I read on the AMD site that they draw 200W a piece.

Why would I need powered risers when a LEPA G 1600w PSU will be in place? That's enough power for 5 cards and 300w to spare.

I've heard of a lot of problems with asrock, I try to avoid them. I got lucky and got an open box deal on a gigabyte FM1 socket for $65. But no 6 pin. http://www.newegg.ca/Product/Product.aspx?Item=N82E16813128515

does this MSI 990FXA-GD65 require shorting pin A1 B17 for pci-e 1x to work?

I have problem with 1x extenders on MSI 990XA-GD55 and I am thinking about changing it for this 990FXA-GD65.

I can confirm that the 990FXA-GD65 needs the presence mod on all PCI-e slots, yes.

thank you

what is this railing stuff?

 not exactly accurate - your cpu will need to support the Pcie lanes for the cards, so if you run multiple cards your cpu (while not having to be high end ) has to support the Pcie channels .

if you are going to try to run more than 4 cards , better to get powered risers .

but you can get away without - don’t skimp on the PSU. - Everyone comes back and say "I wish i had of...."

a couple of questions :

1. do you run CGminer?

2. what do they all hash ?

i'd love to see a screen shot with 6 running ?

What do you mean by mod ? 

To shortpin or..?

I just got some minipcie to pcie16, no issues what so ever, now I can get double the cards per rig!

you should be able to get 6 cards in that puppy. Just fine tune the settings so all the cards are running good together, you may have to tune back each one a bit, but your overall is higher. Make sure ya have the power too.

Something weird is going on.. ive attached 6x 7950 (using powered risers) to the 990FXA-GD65. Rig installed with Ubuntu.
When i boot it up and list devs, it only shows 2 devs..

Any idea?

By the way, do you mind do link the device you are using to have more pcie's ?

 

I am confused.com  :-\ hasn't someone somewhere posted an easy definitive guide on how to build a multi-GPU rig?