Litecoin build for noobs: 3x 7950s (1.8 MH/s) in a $10 crate case

[unixunderground]

Taco, may I ask what iteration of the 7950 you're using in your rig?

I'm putting together one myself, but with all the different models with different clocks, locks, and whatnot, I am completely lost about which one would be the one to buy..

Which ones would you recommend out of these? http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&N=-1&isNodeId=1&Description=7950&x=0&y=0

[tacotime]

this one and no other, guaranteed voltage control and runs extremely cool

http://www.newegg.com/Product/Product.aspx?Item=N82E16814127667

[unixunderground]

That's great, thanks for clearing that up, I'll buy those then.

And also, if I can ask something else, what do you think of this mobo? http://www.newegg.com/Product/Product.aspx?Item=N82E16813128509

The price isn't bad, and the 5 PCIe don't seem bad either.

Provided it'd be a good choice, do you think a somewhat crappy CPU like an Athlon II X2 250  http://www.ebay.com/itm/121077300811?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649 @3Ghz would be enough for running initially one card and up to 5 after a while? (I ordered a 1200W PSU, the Corsair AX1200)

Thanks again!

[nostradamus]

Why the 8 GB of ram?  I thought LTC mining used the onboard GPU ram...

You need the equivalent amount of RAM used on the cards on the system -- it's an opencl bug

What's the bug? I ask b/c I am definitely running both BTC and LTC rigs with GPU RAM > SYS RAM

[fwho]

this one and no other, guaranteed voltage control and runs extremely cool

http://www.newegg.com/Product/Product.aspx?Item=N82E16814127667

I was going to ask about this one: https://www.bitcoinstore.com/visiontek-radeon-hd-7950-graphic-card-3-gb-gddr5-sdram-pci-express-3-0-x16.html but I think your post clarified it for me already.

[TheAce]

hi taco, is possible to use 7970 cards in this setup? does it make some difference in hashing power?
and other question, what if i put those gpus to motherboard directly without cables? would it be a big heating for mobo?

[bitcoinnix]

this one and no other, guaranteed voltage control and runs extremely cool

http://www.newegg.com/Product/Product.aspx?Item=N82E16814127667

What kh/s are you getting from those, exactly?  I see on the hardware comparison page that they vary a bit and I'm trying to forecast if it's worth it to upgrade from my 6870s.
How about wattage?
How about temps?

Have you run them in an enclosed case before?  I'm kind of stuck running GPUs in a case in a room where the sound and temperature are a concern.  I'm running two 6870s at intensity 17 & 18, at about 73C and 79C now inside of a case.

Thanks!

[Delarock]

What do you mean guaranteed voltage control? I have three of these right now, and even though you can move the slider up and down in Afterburner, GPUZ doesn't read any change in voltage. Actually, now that I've looked, neither does the graph in Afterburner.

[Marrs]

Not a bad setup for the price. I built mine a year ago and each level was a add on and its all slides on and apart within a minute. Each motherboard tray pulls out to be serviced if it needs. Each level costs about $15-$20 to make. Some cheap thin aluminum angle with a few gussets makes for a decent structure that open exhausts well. You can see the top two levels I added an aluminum bar to screw the video cards into which was a nice addition to the setup. All the other cards are cable tied to the motherboards rails that hold the acrylic plastic.

Any chance you could provide a bit more detail about how you put your trays together?

[msm595]

If you had to buy a case, what case would you get?

Also, do you mind sharing the config and what program you are using to mine?

[tacotime]

What do you mean guaranteed voltage control? I have three of these right now, and even though you can move the slider up and down in Afterburner, GPUZ doesn't read any change in voltage. Actually, now that I've looked, neither does the graph in Afterburner.

Contact MSI in their forum, they should all allow voltage control through afterburner.

[superdork]

First-   THANKS!!!

Second-   could I substitute 7970 for just a little bit more $$$ and get faster Mhash/s ?

(asking because in checking the chart the 7970 gets very high Mhash/s.... am I missing something? Is it that the 7970 create more heat and need a fan also or something like that? sorry I 'm a noob)

[Joerii]

First, I'd like to share a tip. Just a little something to make life easier for noobs like us.

- If you can't get MSI Afterburner to unlock everything ( that happens for some people, even if you follow all the steps ), download Sapphire TriXX. It doesn't need any unlocking it all, just install it and you're good to go. I have Sapphire 7950's, but it will probably work for other cards too.

Now for an update on how my rig is coming along : Well, it works. Not much to look at yet because I don't have risers yet, so right now it's just a mobo on plastic with 2 7950's connected. Once I find a crate and get my risers I'll post a picture. I had a big headache with the motherboard seemingly not detecting multiple GPU's, and was about to disassemble everything and get a new mobo, when I noticed one of the powercables wasn't connected. That was a big relief and , yes, more then a little bit emberassing. I don't mind sharing that though. Always remember, it's rule number one in hardware troubleshooting. Check all cables caaaaaaarefully. 

My current hurdle is to make the system run with stability. Right now, the card that is NOT hooked up to the screen has no problems. It keeps chugging along at a modest 558 khash/sec. The primary GPU, however, has problems.

-I get visual  artifacts on screen, ( probably due to the settings GUIminer scripts send to the GPU )
- Windows reports a problem with the gpu driver
- Catalyst reports a disabled driver
- after a while the haashrate drops to around 270khash/sec, a little while longer, 7khash/sec ( but Afterburner reports 0 activity on the card. I guess at that point the GPU is asleep and is simply dreaming of mining litecoins hahah

Can anyone help me with thse problems ?

TacoTime, as promised, I've sent my first ever mined litecoin to the adres in GUIminer-script. Thanks for all the info and programming you provide !

[kokojie]

Thanks for the post, I liked the idea and thought it's a fun project, so here's My poorly constructed plastic container rig, 4x 7950, 1200W cooler master PSU, 8GB system ram

[crazy_rabbit]

Thanks for the post, I liked the idea and thought it's a fun project, so here's My poorly constructed plastic container rig, 4x 7950, 1200W cooler master PSU, 8GB system ram

I had a thought for something like that durring the winter. Leave it out side, but upside down so it could have access to fresh air without being covered (the bottom would be open). I ended up using a small unheated glasshouse instead, but it seemed like a cool idea at the time.

[Joerii]

Well that green plastic box has a ...certain charme... I seriously doubt it's open enough to provide 4 7950's with enough cool air. What temperatures do you get after half an hour ?

As I  understand it, one should aim to keep the temperature under 80 degrees c. Above 90 you are really starting to do damage.

My prototype runs up to 74c, and that's with only 2 7950's and no case at all.

[protokol]

Thanks a bunch for this guide mate, It's really helped. And I got the rig up and running pretty smoothly as well.

There's just 2 of the 3 cards in the mobo right now though - I'm still waiting for those PCIe extenders (harder to find than I thought...) but the rig's kicking out a solid 1.2Mh/s and the third card is in my other PC for the moment kicking out an extra ~500 Kh/s. Thought I'd better get them all up and running somehow before the difficulty starts going proper nuts...

I tried putting all 3 cards in the same mobo, but the proximity caused one of the cards to heat up to 85C (with 100% fan override) and was still climbing fast... needless to say I got a bit scared and took it out.

pics to come when it's all complete, and expect a tip tacotime once I mine a few Liteys!!!

 

[Joerii]

Thanks a bunch for this guide mate, It's really helped. And I got the rig up and running pretty smoothly as well.

There's just 2 of the 3 cards in the mobo right now though - I'm still waiting for those PCIe extenders (harder to find than I thought...) but the rig's kicking out a solid 1.2Mh/s and the third card is in my other PC for the moment kicking out an extra ~500 Kh/s. Thought I'd better get them all up and running somehow before the difficulty starts going proper nuts...

I tried putting all 3 cards in the same mobo, but the proximity caused one of the cards to heat up to 85C (with 100% fan override) and was still climbing fast... needless to say I got a bit scared and took it out.

pics to come when it's all complete, and expect a tip tacotime once I mine a few Liteys!!!

 

Heh. Seems like we are in exactly the same spot. Scroll up a few posts and you'll see..it's like you copy pasted my words

[BKM]

Plug the card into the extender and connect remaining power bits.

I want to build one of these just so I can start it with a screwdriver!!!!!

I LOVE that!

I hope there are sparks - harmless and just for effect.

[kokojie]

Well that green plastic box has a ...certain charme... I seriously doubt it's open enough to provide 4 7950's with enough cool air. What temperatures do you get after half an hour ?

As I  understand it, one should aim to keep the temperature under 80 degrees c. Above 90 you are really starting to do damage.

My prototype runs up to 74c, and that's with only 2 7950's and no case at all.

Yeah you are right, the box is really bad for cooling, I couldn't run the 4 cards at max intensity, they would only stably work at intensity 13 on cgminer.