Guide on Building a 10-15MH rig?

[Clayce]

I already saw a few guides on building your own rig, but are there any other guides for building a 10+ MH/s rig?

[1713448276]

1713448276

[1713448276]

1713448276

[1713448276]

1713448276

[profall]

I would build multiple 3 MH/s rigs to reach that goal.

[Clayce]

What guides/links do you recommend?

[crazyates]

Yep, you're looking at 3-4 rigs.

We use this motherboard. Works with 5 cards using those PCIe/USB risers. Find a cheap CPU and a single 8GB RAM stick. We use 2 of these PSUs, as you can run 5 undervolted 280x on only 2 of them, which will get you 3.5MH/s per rig, @ ~1250-1300W, and ~$2500 per rig.

Your biggest factors in price are going to be how cheap you can find your GPUs. And of course, that's also assuming you have the space, equipment, power, and cooling capabilities to run all of these.  

[janos666]

What guides/links do you recommend?

Buy 3 cheap MBs with 6 PCI-E slots on them (like anything with 990FX), 18 R9 290 cards (up to 18 risers with molex power cord), 3 midrange ATX (for the MBs) and either 6 ~1000W ATX or 3 ~2000W server grade power supplies, an ethernet switch, 3x CPUs, 3x2G RAM sticks, 3x 2.5" HDDs or SSDs (optionally 3 pendrivers). Install Debian 8.0 test or Xubuntu 14.04 nightly, AMD 13.19B9.4, set up cgminer, image the drive and clone it twice.

[Clayce]

Yep, you're looking at 3-4 rigs.

We use this motherboard. Works with 5 cards using those PCIe/USB risers. Find a cheap CPU and a single 8GB RAM stick. We use 2 of these PSUs, as you can run 5 undervolted 280x on only 2 of them, which will get you 3.5MH/s per rig, @ ~1250-1300W, and ~$2500 per rig.

Your biggest factors in price are going to be how cheap you can find your GPUs. And of course, that's also assuming you have the space, equipment, power, and cooling capabilities to run all of these.  

Thanks for the awesome advice! So this motherboard should work with 5 Radeon 7950's, or do you recommend the 280x's?

[kalus]

at this point demand for these cards are raising prices everywhere and are backordered in most places in the US.  buy what you can at a reasonable price; i've seen 280x being sold for $600.  people are taking crazy pills.

if you can manage the heat and the expense, get the 280x.  it will be fewer cards for the same hashrate as an equivalent rig with 7950s.  you could run 4x 280x with 1600w (2x800w) power supplies.

if you want to fuck around with your settings, i like the 7950s bios selector switch to allow for custom card voltage.  in a multicard setup this could save money with slightly smaller wattage power supplies.  the 1000w+ power supplies are ridiculously expensive.

[crazyates]

We use this motherboard. Works with 5 cards using those PCIe/USB risers. Find a cheap CPU and a single 8GB RAM stick. We use 2 of these PSUs, as you can run 5 undervolted 280x on only 2 of them, which will get you 3.5MH/s per rig, @ ~1250-1300W, and ~$2500 per rig.

Thanks for the awesome advice! So this motherboard should work with 5 Radeon 7950's, or do you recommend the 280x's?

Yes, it should work with 5 of any GPU. We've got 3 identical rigs using that MB with 290s or 280xs.

I'd recommend a 280x over a 7950. With a 7950, you're looking at either buying used, or paying the same price for a new one as a 280x. The 280x is compatible with VBE7, which is nice (as opposed to the 290s, which are voltage locked no matter what).

at this point demand for these cards are raising prices everywhere and are backordered in most places in the US.  buy what you can at a reasonable price; i've seen 280x being sold for $600.  people are taking crazy pills.

if you can manage the heat and the expense, get the 280x.  it will be fewer cards for the same hashrate as an equivalent rig with 7950s.  you could run 4x 280x with 1600w (2x800w) power supplies.

if you want to fuck around with your settings, i like the 7950s bios selector switch to allow for custom card voltage.  in a multicard setup this could save money with slightly smaller wattage power supplies.  the 1000w+ power supplies are ridiculously expensive.

The problem is no matter what GPU you buy, they're WAY overpriced. I bought a pair of 7950s six months ago for $200/each, mined on them, and then sold them for $300/each. Those 280x MSRP for $299, but are selling for >$400 on almost every website. $500 for a 290 and $600 for a 290x are just crazy.

And yes, 2x800W would work fine. I'm running 2x750W, and pulling <1300W from the wall.

Almost every AMD GPU will have a dual BIOS switch, which will allow you to save the BIOS, tweak it in VBE7, and flash your modified, lower voltage BIOS while still having a backup. That's not something specific to the 7950s.

[kalus]

The problem is no matter what GPU you buy, they're WAY overpriced. I bought a pair of 7950s six months ago for $200/each, mined on them, and then sold them for $300/each. Those 280x MSRP for $299, but are selling for >$400 on almost every website. $500 for a 290 and $600 for a 290x are just crazy.

270x are still pre-rush prices.  (shh)

Almost every AMD GPU will have a dual BIOS switch, which will allow you to save the BIOS, tweak it in VBE7, and flash your modified, lower voltage BIOS while still having a backup. That's not something specific to the 7950s.

which R9 series have you seen the switch?  the original question was comparing 7950s with r9 280s.no R9 2xx GPU i've seen has a bios switch.

[crazyates]

The problem is no matter what GPU you buy, they're WAY overpriced. I bought a pair of 7950s six months ago for $200/each, mined on them, and then sold them for $300/each. Those 280x MSRP for $299, but are selling for >$400 on almost every website. $500 for a 290 and $600 for a 290x are just crazy.

270x are still pre-rush prices.  (shh)

Ya, but density is an issue with them. You gotta buy more MBs, CPUs, RAM, risers, and PSUs to get the same hashrate, which is not cheap. Those 270x do come out slightly ahead of the 280x in terms of Khs/USD according to my math, but not by much. I'd rather have the 280xs.

Almost every AMD GPU will have a dual BIOS switch, which will allow you to save the BIOS, tweak it in VBE7, and flash your modified, lower voltage BIOS while still having a backup. That's not something specific to the 7950s.

which R9 series have you seen the switch?  the original question was comparing 7950s with r9 280s.no R9 2xx GPU i've seen has a bios switch.

I know for a fact that our Gigabyte R9 280x have a dual BIOS switch. Our PowerColor R9 290 cards also have one. I thought all R9s had them?

[Clayce]

I know the GPU prices are pretty crazy right now. As far as I can tell, you can still find some 280x's on ebay for a little under $400. What brand would you recommend, and what should be the max buying price for 280x's?

[kalus]

the original price was close to $300.  but that was november, and i guess the new clearing price is $350-$450 retail.  best shot at getting close to that price is to backorder.  my local shop lets me do this, and i pay for the card when it arrives.

you should do a break-even calculation on whatever price you settle on.  the point at which you break-even should tell you if the price is reasonable for you or not. 

there are a few other threads here that are talking break-even projections of 90-120 days.  that's if the payouts are consistent and sustainable. your max buying price should reflect whether you feel the break-even point is reachable.

because i buy based on price, i buy what's on sale and have no brand loyalty:  asus, HIS, sapphire, gigabyte, etc. all work. i've had good luck with everything except for xfx.  that's just my personal experience, and there's nothing wrong with xfx other than they don't like me.   i know people that have done fine with xfx. 

[crazyates]

What brand would you recommend, and what should be the max buying price for 280x's?

Best brands are Asus, Gigabyte, Sapphire, and MSI.

I've bought PowerColor and had good luck with them, but some people haven't.

Stay away from Diamond, XFX, VisionTek, or HIS. They're nothing more than cheap shit.

Price? That's all up to you. As cheap as you can, IMO.

And ofc, that depends if you're buying used/new.

For just fooling around, I don't mind buying used since it can be significantly cheaper.

For setting up permanent rigs that I plan on running for the next 6-18 months? Everything has to be new.

[Clayce]

Thanks for the replies, I also was thinking of buying one of these rigs, what do you think?
https://bitcointalk.org/index.php?topic=411691.0

[crazyates]

Thanks for the replies, I also was thinking of buying one of these rigs, what do you think?
https://bitcointalk.org/index.php?topic=411691.0

That guy knows what he's doing when it comes to mining, and those rigs look well built, but $3,000 is overpriced. You can buy a brand new 5x 280x rig for that price.

[Clayce]

So checking this https://litecoin.info/Mining_Hardware_Comparison

It shows the R7990 being the fastest GPU at ~1300kh/s. Could it be possible to just get 4 of these into 1 rig for around ~5mh/s per rig?

[crazyates]

So checking this https://litecoin.info/Mining_Hardware_Comparison

It shows the R7990 being the fastest GPU at ~1300kh/s. Could it be possible to just get 4 of these into 1 rig for around ~5mh/s per rig?

Yes, I think I've seen some people on this forum running 4x7990s. The problem is that they're like 800-900USD used, and you can't buy them new anywhere. They also run pretty hot, IIRC. Still, makes for a nice, dense rig.

[Clayce]

So checking this https://litecoin.info/Mining_Hardware_Comparison

It shows the R7990 being the fastest GPU at ~1300kh/s. Could it be possible to just get 4 of these into 1 rig for around ~5mh/s per rig?

Yes, I think I've seen some people on this forum running 4x7990s. The problem is that they're like 800-900USD used, and you can't buy them new anywhere. They also run pretty hot, IIRC. Still, makes for a nice, dense rig.

Alright cool thanks again for the replies, I think Ive narrowed it down. Basically I have ~10k to invest into the rigs. I can either buy them, or build them..

As far as building, should I either look for 280x's for like 4-5rigs, or should I look into the 7990s for 3-4 rigs? My main goal is simply max hashing power for the buck.

[crazyates]

As far as building, should I either look for 280x's for like 4-5rigs, or should I look into the 7990s for 3-4 rigs? My main goal is simply max hashing power for the buck.

280x It's the best card out there right now.

[Clayce]

As far as building, should I either look for 280x's for like 4-5rigs, or should I look into the 7990s for 3-4 rigs? My main goal is simply max hashing power for the buck.

280x It's the best card out there right now.

Alright cool, I just bought a Sapphire Dual-X R9 280x for $370 (seem decent??) on eBay, might try to find 3-4 more in the same price range then get this first rig started. I might have to PM you for some more newbie questions on other details lol! Thanks for the help!