Cheapest Core i7 Machine - 0.5 BTC Bounty [PAID] - page 3.

azwccc

sr. member

Activity: 243

Merit: 250

Quote from: bytemaster on October 31, 2013, 10:33:52 PM

1 GB is enough ram to do the proof of work and adding additional RAM will not accelerate the process by more than .05% with almost no gains beyond 2 GB... make sure there is room for OS and wallet app.

The proof of work is structured so that by the time you use 768 MB of ram (entire nonce search space) there is a 99% chance of finding 1-2 potential hashes.

Once you exhaust the nonce search space you clear the RAM and start over.

Increasing CPU speed helps until the bottleneck is the memory bus and is worthless beyond that point.

If you have less than 768 MB of ram your performance falls exponentially such that 512MB of RAM cuts your performance down to 10% (SWAG) of what it would be with the full amount of RAM.

Thanks,

Today, DDR3-2400 Ram is not expensive, and MB support up to 3000MHz overclock (although higher cas latency). And considering I7 cpu can only saturate 50% DDR3-1600, improving cpu speed/thread is the key, right?

Is 768M for a single core/thread or entire system?

It is so hard to build a proper miner before release. Do you have plan to get into miner business?

ZirconiumX

full member

Activity: 286

Merit: 100

Quote from: bytemaster on October 31, 2013, 06:02:20 PM

Quote from: ZirconiumX on October 31, 2013, 05:07:06 PM

Quote from: bytemaster on October 31, 2013, 03:58:28 PM

I was able to build the following:AMD FX-6300 BULLDOZER SIX CORE 3.5GHz Biostar A960D+ 2GB DDR3 500GB HDD for $367 shipped.
http://www.ebay.com/itm/291007635830

Unfortunately it comes with an unnecessary DVD drive which I suspect could save another $10 if someone can source it elsewhere.

And the best response I have gotten thus far is:

Or Build it Ourself Intel system:

Power Supply: $30
Case: $29
Mother Board: $65
3.2 Ghz Quad Core i5: $190
2 GB DDR3 RAM: $20
250 GB 7200 Disk $50
Assembly: $50
-------------------------------------------
Total: $434

So the question is, for momentum what is the difference in performance for a Quad Core i5 at 3.2 vs a Six Core AMD at 3.5 Ghz? Benchmarks show memory throughput is about even.

You'll find that that is because the memory is bottlenecked on both machines.

You could put a dual-core in there and if you pump it hard enough, bottleneck the memory.

This seems to be less of a "who can build the cheapest computer" and more of a "who can bottleneck the memory for the least amount of money".

DDR3-2133 anyone?

Matthew:out

Well, it is all about throughput per dollar. I know that a 3.4 Ghz Core i7 with 8 threads going has a hard time hitting the theoretical memory bus limits because speed increases linearly as I add cores to the problem. My estimates show that an i7 can saturate about 50% of the memory bus running 1600 Mhz DDR3 RAM (using SHA512 to fill RAM). So the processor matters a lot. There are a lot of memory delays so hyper threading helps a lot. That said, memory is accessed in a random manner and so the bus is unable to operate at max efficiency.

All of that said, a CPU that was 100x faster would clearly hit the memory bus limit and thus hinder use of custom ASIC to replace CPU alone.

I suppose, then, that fast memory is pretty much a must-have. I wonder how much of a performance gain it will have, though. Would it make it worth the money?

Would upgrading the fx-6300 to an fx-8320 make a significant difference? Would it be better value for money to try an fx-8120?

So many questions.

Matthew:out

ZirconiumX

full member

Activity: 286

Merit: 100

Quote from: balanghai on October 31, 2013, 10:39:23 PM

I think the bounty belongs to me. Here's my ace:

http://www.neo.com.ph/products/elan-series

My tip jar:

1HC4XbPm6sAGr3CdahPRq2iJyJhbrryXo

He says, offering up something that has several major problems.

1) The cheapest model is $530 - I beat you by $80.
2) It's a laptop - laptops are designed for low powet, not high performance.
3) It's in the philipines - import tax and delivery costs!

Matthew:out

balanghai

sr. member

Activity: 364

Merit: 253

I think the bounty belongs to me. Here's my ace:

http://www.neo.com.ph/products/elan-series

My tip jar:

1HC4XbPm6sAGr3CdahPRq2iJyJhbrryXo

bytemaster

hero member

Activity: 770

Merit: 566

fractally

1 GB is enough ram to do the proof of work and adding additional RAM will not accelerate the process by more than .05% with almost no gains beyond 2 GB... make sure there is room for OS and wallet app.

The proof of work is structured so that by the time you use 768 MB of ram (entire nonce search space) there is a 99% chance of finding 1-2 potential hashes.

Once you exhaust the nonce search space you clear the RAM and start over.

Increasing CPU speed helps until the bottleneck is the memory bus and is worthless beyond that point.

If you have less than 768 MB of ram your performance falls exponentially such that 512MB of RAM cuts your performance down to 10% (SWAG) of what it would be with the full amount of RAM.

azwccc

sr. member

Activity: 243

Merit: 250

Does this means for the I7 with DDR3-1600 combination, cpu is the bottleneck?

If three or more I7/equivalent work with DDR3-1600, memory speed will become the bottleneck?

Does the memory size matters? I suppose it will increase the speed also. Or 2GB is enough?

bytemaster

hero member

Activity: 770

Merit: 566

fractally

Quote from: ZirconiumX on October 31, 2013, 05:07:06 PM

Quote from: bytemaster on October 31, 2013, 03:58:28 PM

I was able to build the following:AMD FX-6300 BULLDOZER SIX CORE 3.5GHz Biostar A960D+ 2GB DDR3 500GB HDD for $367 shipped.
http://www.ebay.com/itm/291007635830

Unfortunately it comes with an unnecessary DVD drive which I suspect could save another $10 if someone can source it elsewhere.

And the best response I have gotten thus far is:

Or Build it Ourself Intel system:

Power Supply: $30
Case: $29
Mother Board: $65
3.2 Ghz Quad Core i5: $190
2 GB DDR3 RAM: $20
250 GB 7200 Disk $50
Assembly: $50
-------------------------------------------
Total: $434

So the question is, for momentum what is the difference in performance for a Quad Core i5 at 3.2 vs a Six Core AMD at 3.5 Ghz? Benchmarks show memory throughput is about even.

You'll find that that is because the memory is bottlenecked on both machines.

You could put a dual-core in there and if you pump it hard enough, bottleneck the memory.

This seems to be less of a "who can build the cheapest computer" and more of a "who can bottleneck the memory for the least amount of money".

DDR3-2133 anyone?

Matthew:out

Well, it is all about throughput per dollar. I know that a 3.4 Ghz Core i7 with 8 threads going has a hard time hitting the theoretical memory bus limits because speed increases linearly as I add cores to the problem. My estimates show that an i7 can saturate about 50% of the memory bus running 1600 Mhz DDR3 RAM (using SHA512 to fill RAM). So the processor matters a lot. There are a lot of memory delays so hyper threading helps a lot. That said, memory is accessed in a random manner and so the bus is unable to operate at max efficiency.

All of that said, a CPU that was 100x faster would clearly hit the memory bus limit and thus hinder use of custom ASIC to replace CPU alone.

ZirconiumX

full member

Activity: 286

Merit: 100

Quote from: bytemaster on October 31, 2013, 03:58:28 PM

I was able to build the following:AMD FX-6300 BULLDOZER SIX CORE 3.5GHz Biostar A960D+ 2GB DDR3 500GB HDD for $367 shipped.
http://www.ebay.com/itm/291007635830

Unfortunately it comes with an unnecessary DVD drive which I suspect could save another $10 if someone can source it elsewhere.

And the best response I have gotten thus far is:

Or Build it Ourself Intel system:

Power Supply: $30
Case: $29
Mother Board: $65
3.2 Ghz Quad Core i5: $190
2 GB DDR3 RAM: $20
250 GB 7200 Disk $50
Assembly: $50
-------------------------------------------
Total: $434

So the question is, for momentum what is the difference in performance for a Quad Core i5 at 3.2 vs a Six Core AMD at 3.5 Ghz? Benchmarks show memory throughput is about even.

You'll find that that is because the memory is bottlenecked on both machines.

You could put a dual-core in there and if you pump it hard enough, bottleneck the memory.

This seems to be less of a "who can build the cheapest computer" and more of a "who can bottleneck the memory for the least amount of money".

DDR3-2133 anyone?

Matthew:out

bytemaster

hero member

Activity: 770

Merit: 566

fractally

I was able to build the following:AMD FX-6300 BULLDOZER SIX CORE 3.5GHz Biostar A960D+ 2GB DDR3 500GB HDD for $367 shipped.
http://www.ebay.com/itm/291007635830

Unfortunately it comes with an unnecessary DVD drive which I suspect could save another $10 if someone can source it elsewhere.

And the best response I have gotten thus far is:

Or Build it Ourself Intel system:

Power Supply: $30
Case: $29
Mother Board: $65
3.2 Ghz Quad Core i5: $190
2 GB DDR3 RAM: $20
250 GB 7200 Disk $50
Assembly: $50
-------------------------------------------
Total: $434

So the question is, for momentum what is the difference in performance for a Quad Core i5 at 3.2 vs a Six Core AMD at 3.5 Ghz? Benchmarks show memory throughput is about even.

ZirconiumX

full member

Activity: 286

Merit: 100

I have sent you - what I think is - a pretty good deal via PM.

Matthew:out

bytemaster

hero member

Activity: 770

Merit: 566

fractally

Quote from: ZirconiumX on October 30, 2013, 05:01:07 AM

Quote from: bytemaster on October 30, 2013, 02:07:03 AM

I am offering a 0.5 BTC bounty to the individual who can spec out the cheapest possible Quad Core x86 system for mining momentum proof of work.

1) Must have 2+ GB of RAM
2) Must have 4+ cores
3) Must run Linux and have at least 32 GB of storage.
4) Must have a case.
5) Must have ethernet.

Everything else is optional, smaller is better.

If the system is put together from parts, add $50 to the price for labor.

The spec must include links where such a system can be sourced in quantity. IE: ebay and other second-hand sources do not count.

Does this have to be explicitly a Core i7 machine?

What about Hyperthreading - is a dual core with HT considered a quad-core?

Matthew:out

Hyper threading counts as 50% of a core. I will attempt to normalize CPU performance when comparing prices.

ZirconiumX

full member

Activity: 286

Merit: 100

Quote from: bytemaster on October 30, 2013, 02:07:03 AM

I am offering a 0.5 BTC bounty to the individual who can spec out the cheapest possible Quad Core x86 system for mining momentum proof of work.

1) Must have 2+ GB of RAM
2) Must have 4+ cores
3) Must run Linux and have at least 32 GB of storage.
4) Must have a case.
5) Must have ethernet.

Everything else is optional, smaller is better.

If the system is put together from parts, add $50 to the price for labor.

The spec must include links where such a system can be sourced in quantity. IE: ebay and other second-hand sources do not count.

Does this have to be explicitly a Core i7 machine?

What about Hyperthreading - is a dual core with HT considered a quad-core?

Matthew:out

bytemaster

hero member

Activity: 770

Merit: 566

fractally