Cheapest Core i7 Machine - 0.5 BTC Bounty [PAID]

[ZirconiumX]

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

[ZirconiumX]

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

[azwccc]

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]

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?

A higher CAS latency at those speeds doesn't necessarily mean the memory is slower to respond.

Let's assume the we have two sticks of memory, one at DDR3-1333 CAS 5-10-10 ( for example), and one at DDR3-2666 CAS 10-20-20. Which is faster?

Because CAS latency is given in clock cycles, a doubling of bus speed means that the CAS latency will double. However, since twice as many clock cycles happen in the same amount of time, the answer is, they are both exactly the same.

I suppose we have the question of higher bus speed, or lower latency...

Matthew:out

[gadman2]

http://pcpartpicker.com/p/1VWD5

406$+50 build

Or if you wanted a real i7:

http://pcpartpicker.com/p/1VWJ3

415$+50 build

Same as above with 2gb 1600 memory:

http://pcpartpicker.com/p/1VWML

418$+50 build

I believe I have the lowest price at the moment with 100% brand new parts following the rules. Address in sig

[bytemaster]

http://pcpartpicker.com/p/1VWD5

406$+50 build

Or if you wanted a real i7:

http://pcpartpicker.com/p/1VWJ3

415$+50 build

Same as above with 2gb 1600 memory:

http://pcpartpicker.com/p/1VWML

418$+50 build

I believe I have the lowest price at the moment with 100% brand new parts following the rules. Address in sig

You are forgetting power supply which adds $40 to each of your quotes.

Opps... I just noticed the case included a 400 watt power supply... Good work!

[bytemaster]

The mining proof is well defined.  The best algorithm for performing the proof is yet to be developed.

Proof:
 

Code:

	
       	#define MAX_MOMENTUM_NONCE  (1<<26)
	#define SEARCH_SPACE_BITS 50
	#define BIRTHDAYS_PER_HASH 8

        bool momentum_verify( uint256 midHash, uint32_t a, uint32_t b )
        {
		if( a == b ) return false;
                if( a == 0 ) return false;
                if( b == 0 ) return false;
		if( a > MAX_MOMENTUM_NONCE ) return false;
		if( b > MAX_MOMENTUM_NONCE ) return false;
		return (getBirthdayHash(midHash,a)==getBirthdayHash(midHash,b));
	}

	uint64_t getBirthdayHash(uint256 midHash, uint32_t a)
        {
           char  hash_tmp[sizeof(midHash)+4];
           memcpy(hash_tmp+4, (char*)&midHash, sizeof(midHash) );
           uint32_t* index = (uint32_t*)hash_tmp;
           *index = a-a%BIRTHDAYS_PER_HASH;

           uint64_t  result_hash[8];
	   SHA512((unsigned char*)hash_tmp, sizeof(hash_tmp), (unsigned char*)&result_hash);

           return result_hash[a%BIRTHDAYS_PER_HASH]>>(64-SEARCH_SPACE_BITS);
	}

Factors in Performance:
How many SHA512 hashes per second can a CPU achieve.
For each SHA512 hash performed, a hashmap must be populated with eight 64 bit keys and 32 bit values.
The minimum memory bandwidth requirement is therefore:  12*8*Sha512PerSec  bytes per second.
The memory is accessed randomly and is transferred in blocks of 64 bytes based upon the cache line size of the CPU.
The effective memory bandwidth requirement is therefore: 64*8*Sha512PerSec  bytes per second.

A 3.4 Ghz Core i7 can generate 2 million Sha512/sec per core.   I will be generous and assume 12 million Sha512/sec when all cores + hyper-threading are saturated.
12 million * 512 bytes per second is 6 Gigabytes per second on the memory bus assuming no other overhead.

Transfer rate on RAM is 6.4 GB/s per channel theoretical.   So when you factor in all of the other random overhead, the fact memory access isn't perfectly pipelined or sequential then it becomes very clear that memory bandwidth and CPU power must be paired.   

The fastest possible machine may be a 12 core Mac Pro with DDR4... but this wouldn't be the lowest price/hash.  

 

[MineMind]

Xeon E3's are rebadged and binned i7's that are compatible with most motherboards out there.
Readycache drives can be used as boot drives but require additional fuckery in many cases, so I am not going to use one in my build list. I refuse to use BioStar or Diablotek anything due to reliability. I could not find information on most of the Biostar motherboards in reference to the latest shipping units requiring a BIOS flash or not, which is another reason i chose the ASRock or alternatively MSI models. This is important as it would require additional time, fuckery, and another CPU to accomplish. Notice the compatibility flag on his.

That being said:
http://pcpartpicker.com/p/1W14w
Base Total:    $357.95    
Mail-in Rebates:    -$25.00    
Shipping:    $4.99    
Total:    $337.94

Though, all of the ones using the Kingston module should add an additional 99 cents as the Amazon one has one left and requires 35+$ spent to have free S/H on that item.

I can configure for one retailer if you like or mix parts better for no MIRs. If you buy today it would be under 320 with code NAFSAVE25NOV1R shipped totally from newegg and also assuming a free shoprunner account.

[bytemaster]

http://pcpartpicker.com/p/1VWD5

406$+50 build

Or if you wanted a real i7:

http://pcpartpicker.com/p/1VWJ3

415$+50 build

Same as above with 2gb 1600 memory:

http://pcpartpicker.com/p/1VWML

418$+50 build

I believe I have the lowest price at the moment with 100% brand new parts following the rules. Address in sig

You are forgetting power supply which adds $40 to each of your quotes.

Opps... I just noticed the case included a 400 watt power supply... Good work!

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    

Based upon benchmarks the i7 system is 1.34x faster overall so I would have to handicap my AMD system by a similar factor which would put the price at $491 vs $470 for your i7 based system.  I suspect that I could spec an AMD system that was slightly cheaper once I remove the DVD drive and use the same 32 GB SSD drive and case that you mentioned.     The there is the long-term electric cost to factor in which would give the i7 a clear edge.    

My conclusion is that you are very much in the lead in the price/performance metric.  I will give it another day before I declare a winner and pay the bounty.

[bytemaster]

Xeon E3's are rebadged and binned i7's that are compatible with most motherboards out there.
Readycache drives can be used as boot drives but require additional fuckery in many cases, so I am not going to use one in my build list. I refuse to use BioStar or Diablotek anything due to reliability. I could not find information on most of the Biostar motherboards in reference to the latest shipping units requiring a BIOS flash or not, which is another reason i chose the ASRock or alternatively MSI models. This is important as it would require additional time, fuckery, and another CPU to accomplish. Notice the compatibility flag on his.

That being said:
http://pcpartpicker.com/p/1W14w
Base Total:    $357.95    
Mail-in Rebates:    -$25.00    
Shipping:    $4.99    
Total:    $337.94

Though, all of the ones using the Kingston module should add an additional 99 cents as the Amazon one has one left and requires 35+$ spent to have free S/H on that item.

I can configure for one retailer if you like or mix parts better for no MIRs. If you buy today it would be under 320 with code NAFSAVE25NOV1R shipped totally from newegg and also assuming a free shoprunner account.

Mail-in Rebates are labor and delay.   You also didn't factor in labor.  So That puts your price at $412.     The improved reliability is a plus in your camp, though the CPU is 3.1 Ghz vs 3.4+ so you currently have the edge for the best system.

[bytemaster]

I can configure for one retailer if you like or mix parts better for no MIRs. If you buy today it would be under 320 with code NAFSAVE25NOV1R shipped totally from newegg and also assuming a free shoprunner account.

This would be great and I will probably order one if I can get it all in one place because that will also save time and money. 

[MineMind]

Gathering all that right now. Please don't forget the CPU has Turbo to 3.5ghz and is a 69 W CPU.
http://ark.intel.com/products/65734/

[bytemaster]

Gathering all that right now. Please don't forget the CPU has Turbo to 3.5ghz and is a 69 W CPU.
http://ark.intel.com/products/65734/

Turbo doesn't mean much for 100% mining load unless I liquid cool the unit

[bytemaster]

Gathering all that right now. Please don't forget the CPU has Turbo to 3.5ghz and is a 69 W CPU.
http://ark.intel.com/products/65734/

Note: 25.6 GB/s Max Memory Bandwidth   

Thus my calculations show we are using about 25% of the MAX theoretical memory bandwidth.   Close to 50% of the practical memory bandwidth.  An ASIC would be limited to perhaps 4x gains if all they did was replace the CPU and perhaps 10x gains if they used very special purpose state of the art memory.   Of course, I doubt they could do these things in a machine costing less than $4000 so there is little cost/benefit to creating an ASIC for this

[MineMind]

http://pcpartpicker.com/p/1W1KP
+ code NAFSAVE25NOV1R = 301.94
+ Free month shoprunner (Free 2-day shipping) = 299.95 ( https://www.shoprunner.com/non_member/home/ )
+ TCB 1-2% Cashback ( 3-6$~ ).

If anything just scale the CPU accordingly... it's still a cheaper build overall and the binned Ivys can't be beat for wattage. Check it out, no matter how you spec it, Ivy i7 will always lose the $/W and $/Ghz battle: http://pcpartpicker.com/p/1W2jt

If you wanted more IPC, the Haswell v3 is currently cheaper than the Ivy line in terms of build:
http://pcpartpicker.com/p/1W2D2
Total:    $304.94
+ code NAFSAVE25NOV1R = 279.94
+ SR -1.99 S/H = 277.95

[bytemaster]

You left off the memory in your latest build.

[MineMind]

WUPS. I think it cut it off when i switched vendor to a specific one.

http://pcpartpicker.com/p/1W43u

2x 1GB 1600 modules for dual-channel, CAS9, and heatspreaders for 1$~ less @ NewEgg vs the Kingston and Mushkin modules @ CAS11, single, and no HS.

Total: $331.93 - 26.99 (CC + SR) = 304.94

Same build with Ivy slightly more, at a lower ICP+wattage, but has turbo. http://pcpartpicker.com/p/1W4nT

[azwccc]

http://www.portatech.com    (if never heard, http://www.resellerratings.com/store/PortaTech)
choose barebones computer (FREE Assembly & Testing Included)

Barebones w/ Intel Core i5 / i7 (Socket 1150)
  w/ Core i5 4670 (4 x 3.8GHz CPU - 6MB Cache +1200MHz Graphics)
  ASRock H81M-DGS
  Systems - CPU Fan Only
  2GB DDR3 1600MHz (1 x 2GB - Single Module)
  500GB 7200RPM SATA3 6gb/sec - Hard Drive
  Standard Value Mid-Tower Case
  400 Watt Power Supply
  Standard - Build, Burn-in, Test & Ship Out in Approx 3 to 5 Business Days
  Barebones - 1 Year

$359.88 shipped, they don't have a good choice of hard drive, but no labor fee.
I5-4670 is good in benchmark

If replace the CPU with  I5-4430, $333.88.

[bytemaster]

http://www.portatech.com    (if never heard, http://www.resellerratings.com/store/PortaTech)
choose barebones computer (FREE Assembly & Testing Included)

Barebones w/ Intel Core i5 / i7 (Socket 1150)
  w/ Core i5 4670 (4 x 3.8GHz CPU - 6MB Cache +1200MHz Graphics)
  ASRock H81M-DGS
  Systems - CPU Fan Only
  2GB DDR3 1600MHz (1 x 2GB - Single Module)
  500GB 7200RPM SATA3 6gb/sec - Hard Drive
  Standard Value Mid-Tower Case
  400 Watt Power Supply
  Standard - Build, Burn-in, Test & Ship Out in Approx 3 to 5 Business Days
  Barebones - 1 Year

$359.88 shipped, they don't have a good choice of hard drive, but no labor fee.
I5-4670 is good in benchmark

If replace the CPU with  I5-4430, $333.88.

This is an awesome website... looking over the various machines this is what I found:

Core i7 3.9 Ghz
2GB
$369.78 + $20 USB Stick with Linux on it for HD total  $389

Based upon their performance numbers, the Core i7 is 25% faster and yet only costs 8% More. 

I suspect any system running full tilt will need to spend another $50 in cooling, but that is a constant offset that also favors the i7 over the i5.

Overall, PortaTech seems to be the best source for these systems. 

AMD FX8320 @ 8 x 4.0GHz
$242.93 + $20 USB Stick with Linux
Adjusted for 10% less performance... $270
Adjusted for extra power used over 1 year... $370 (100 Watt difference, 24x7, $.1 KWH)


I am inclined to say that azwccc is in the lead so far.

[MineMind]

I was able to spec it at that same site through pricewatch.com ( http://www.pricewatch.com/price/motherboard_combos/fx-8320 ):
Description    Unit Price    
   cb-amd   Combo w/ AMD FX (Socket AM3+)
  w/ AMD FX8320 - Eight-Core (8 x 4.0GHz - 16MB Cache)
  ASRock 960GM-VGS3
  Systems - CPU Fan Only
  2GB DDR3 1600MHz (1 x 2GB - Single Module)
  500GB 7200RPM SATA3 6gb/sec - Hard Drive
  Premium Assemble, Setup, Pretest, & Set CPU FSB & Power / Cooling
  400 Watt Power Supply
  Combo - 1 Year   $305.78   Remove

Barebones w/ AMD FX (Socket AM3+)
  w/ AMD FX8350 - Eight-Core (8 x 4.2GHz - 16MB Cache)
  ASRock 960GM-VGS3
  Systems - CPU Fan Only
  2GB DDR3 1600MHz (1 x 2GB - Single Module)
  500GB 7200RPM SATA3 6gb/sec - Hard Drive
  Standard Value Mid-Tower Case
  400 Watt Power Supply
  Standard - Build, Burn-in, Test & Ship Out in Approx 3 to 5 Business Days
  Barebones - 1 Year   $327.88

Granted, if you're willing to go i5 I can go much lower. SSD and solid PSU in addition to dual channel memory that is actually good seems to be missing from these benchmarks. You're going to starve any 8 core setup in single.

If you're willing to go AMD. This isn't including the -25$, cashback, or free 2day if you get in fast.
http://pcpartpicker.com/p/1We5D Total:    $263.93
http://pcpartpicker.com/p/1We6R Total:    $303.93
http://pcpartpicker.com/p/1We8m Total:    $343.93

If you're willing to go USB drive, get a 3.0 as 3.0 USB is better, even in USB 2.0 slots.
http://pcpartpicker.com/p/1WeeH + http://www.newegg.com/Product/Product.aspx?Item=N82E16820141628