Mining rig extraordinaire - the Trenton BPX6806 18-slot PCIe backplane [PICS]

[rjk]

Why would 7970s get you 1 ghs? Everywhere else it says 800 mhs...

I said 7990. It is a different card. 7970 does not get 800 mhash either, unless perhaps it is extremely overclocked with something other than water cooling. 7970 gets 550 mhash stock, and 650 OCed on air.

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[awigaxeh-443]

so you yourself just proved how bad the idea was lol

[rjk]

so you yourself just proved how bad the idea was lol

You don't seem to be able to understand the motivations for this. That's fine, leave me to it.

[RandyFolds]

so you yourself just proved how bad the idea was lol

And you just proved that you don't understand that density is a massively important factor in mining farms...

[awigaxeh-443]

so you yourself just proved how bad the idea was lol

You don't seem to be able to understand the motivations for this. That's fine, leave me to it.

State your motivations then, I'm exploring all avenues with bitcoin mining

[rjk]

so you yourself just proved how bad the idea was lol

You don't seem to be able to understand the motivations for this. That's fine, leave me to it.

State your motivations then, I'm exploring all avenues with bitcoin mining

See RandyFolds' comment above.

[foggyb]

Run the numbers again. Sure it is fairly bad pricewise, but it has the potential of being actually quite efficient, both on electricity and more importantly on space. Instead of having a CPU/RAM/mobo for every 8GPUs, I have 2 CPUs (could be 1 if I wanted), some RAM, and a mobo for up to 36 GPUs (including dual-GPU cards).

I assume CPU cycles will start to become significant with that many GPU's and miner threads. Will a single core CPU be enough to run all of that without becoming a bottleneck?

[PatrickHarnett]

so you yourself just proved how bad the idea was lol

You don't seem to be able to understand the motivations for this. That's fine, leave me to it.

State your motivations then, I'm exploring all avenues with bitcoin mining

Read post #1

"insane crazy build project" because he can.

Otherwise I recommend you read about the questing beast and Pellinore.

[1l1l11ll1l]

so you yourself just proved how bad the idea was lol

You don't seem to be able to understand the motivations for this. That's fine, leave me to it.

State your motivations then, I'm exploring all avenues with bitcoin mining

Because his 1 rig would replace this ENTIRE wall:

[1l1l11ll1l]

Run the numbers again. Sure it is fairly bad pricewise, but it has the potential of being actually quite efficient, both on electricity and more importantly on space. Instead of having a CPU/RAM/mobo for every 8GPUs, I have 2 CPUs (could be 1 if I wanted), some RAM, and a mobo for up to 36 GPUs (including dual-GPU cards).

I assume CPU cycles will start to become significant with that many GPU's and miner threads. Will a single core CPU be enough to run all of that without becoming a bottleneck?

I would say that it wouldn't become a bottleneck. the BFL singles can be stacked up to 100 units on 1 machine. That'd be more than 80GH/s with 1 CPU.

[malevolent]

Run the numbers again. Sure it is fairly bad pricewise, but it has the potential of being actually quite efficient, both on electricity and more importantly on space. Instead of having a CPU/RAM/mobo for every 8GPUs, I have 2 CPUs (could be 1 if I wanted), some RAM, and a mobo for up to 36 GPUs (including dual-GPU cards).

I assume CPU cycles will start to become significant with that many GPU's and miner threads. Will a single core CPU be enough to run all of that without becoming a bottleneck?

I would say that it wouldn't become a bottleneck. the BFL singles can be stacked up to 100 units on 1 machine. That'd be more than 80GH/s with 1 CPU.

Rjk will have to choose a set of OS, drivers and SDK without the 100% CPU bug, otherwise it is possible that the GPUs will not be utilized in 100% (that's what I have with 12.1 and 2.6, where I have to make the miner use all 4 cpu cores (got 5 gpus), if it's 1-3 then the GPUs will work at 70-95% of their proper speed.

[phorensic]

Why would 7970s get you 1 ghs? Everywhere else it says 800 mhs...

I said 7990. It is a different card. 7970 does not get 800 mhash either, unless perhaps it is extremely overclocked with something other than water cooling. 7970 gets 550 mhash stock, and 650 OCed on air.

I've got my 7970 at 710Mh/s right now, on air.  1250MHz core, voltage bumped up with Sapphire Trixx.

[rjk]

I assume CPU cycles will start to become significant with that many GPU's and miner threads. Will a single core CPU be enough to run all of that without becoming a bottleneck?

I would say that it wouldn't become a bottleneck. the BFL singles can be stacked up to 100 units on 1 machine. That'd be more than 80GH/s with 1 CPU.

Rjk will have to choose a set of OS, drivers and SDK without the 100% CPU bug, otherwise it is possible that the GPUs will not be utilized in 100% (that's what I have with 12.1 and 2.6, where I have to make the miner use all 4 cpu cores (got 5 gpus), if it's 1-3 then the GPUs will work at 70-95% of their proper speed.

Well, if I am forced to use virtualization due to AMD's shitty drivers, then I run into some major issues with CPU and RAM. As in, I will need a lot more, and I will need it to be far more modern. Specifically, I need VT-d, and even then it has never been tested and proven to work.

Why would 7970s get you 1 ghs? Everywhere else it says 800 mhs...

I said 7990. It is a different card. 7970 does not get 800 mhash either, unless perhaps it is extremely overclocked with something other than water cooling. 7970 gets 550 mhash stock, and 650 OCed on air.

I've got my 7970 at 710Mh/s right now, on air.  1250MHz core, voltage bumped up with Sapphire Trixx.

Sweet! What's the power draw like? Any extra voltage?

[awigaxeh-443]

there is a difference between density and volume

[CleverMiner]

800mhs ? , you can get ~750mhs at 1.05v on 5890, how can you expect any less than 1ghs on a 7990 ?  I'd aim for 1.4ghs or more...

[DeathAndTaxes]

I assume CPU cycles will start to become significant with that many GPU's and miner threads. Will a single core CPU be enough to run all of that without becoming a bottleneck?

More than enough.  cgminer uses about 15% of a sempron 145 (singlecore, undervolted & underclocked to 1.8Ghz)  when running 4x5970s (8 GPUs).  

A more capable CPU could likely have 32+ GPUs without breaking 50% load.  Then again with AMD crappy drivers we likely will never find out.

[DeathAndTaxes]

800mhs ? , you can get ~750mhs at 1.05v on 5890, how can you expect any less than 1ghs on a 7990 ?  I'd aim for 1.4ghs or more...

Because the dual cards tend to be lower clocked and have less powerful VRMs (3 phase vs 4 phase).  A 5970 gets about 1.5x a 5870. A 6990 gets about 1.5x a 6970.  A 7990 then will likely get about 1.5x a 7970.  1GH/s seems likely.  With a heavy overclock maybe 1.2 GH/s.  Then again a rig of 18 cards is never going to be clocked as high as a single GPU rig.

[RandyFolds]

there is a difference between density and volume

To what is this referencing?

Yes, of course there is a difference...one measures displacement, and the other measures the ratio of mass to displacement. Still doesn't change the fact that floorspace is money.

[rjk]

Still doesn't change the fact that floorspace is money.

Not in mom's basement!

[minero1]

Jesus! you guys again with the BFL singles, sure they are pretty efficient but let's face it they are LAME, insipid. I like RJK's spirit he not only has the money to burn on this things but he also is doing it for fun (and space efficiency). 

i myself wouldn't be as engaged in bitcoin if it wasn't because of the GPUs, i'm (was?) a gamer and i would've never thought of getting so many GPUs THAT I CAN EXPLAIN/JUSTIFY TO MY WIFE! Man i love this thing, i could be all day long testing Mobos, PCIe Slots, PSUs, measuring stuff, you now what i mean.

Also, say bitcoin crashes tomorrow, god forbid, you end up with your lame boxes doing what, selling SHA-256 brute forcing? good luck with that. I would throw one hell of an HD gaming LAN party if that happens, and sell some GPUs, and give some to my friends/family so they can experience the thing the always hear but never get, or maybe take pictures of me laying down in a bed of GPUs just because i can, sure it would be THE geek sexappeal, or just set up a render farm with some apps that take advantage of Radeons as if they are Fire Gls and sell the service, setup a high-end gaming cafe, and a lot more

Some are here for the money, others are here for the fun, i am here for both