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Thread: How to justify a 6 core build? |
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Thread Status: Active Total posts in this thread: 20
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sk..
Master Cruncher http://s17.rimg.info/ccb5d62bd3e856cc0d1df9b0ee2f7f6a.gif Joined: Mar 22, 2007 Post Count: 2324 Status: Offline Project Badges: 
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Interesting Ikea hack, but one big GPU on the right project could do more than all those systems. It would also be less expensive, easier to setup, and not such a fire hazard! You can do similar things with GPU's
----------------------------------------"If that happens, crunching farm economy turns into a game of finding the cheapest components that will support the largest number of graphics cards" Depends on the science app. Some apps can run 99.9% on the GPU, while some require significant CPU input. So it could well be the case that a GPU heavy rig would have performance issues. Other factors include PCIE width, RAM, HDD, PSU... You just can't hook up a GTX580 on the one PCIE slot of an Atom system and expect great GPU performance. Then there are all those other projects that don't use GPU's - you would still want to support them. [Edit 1 times, last edit by skgiven at Dec 17, 2011 11:55:09 AM] |
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Ingleside
Veteran Cruncher Norway Joined: Nov 19, 2005 Post Count: 974 Status: Offline Project Badges: 
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Just using a not particularly accurate rule of thumb calculation on pricing 3(4) separate rigs built solely for crunching I arrive at the following purchase prices... 1. X58 + 980x = £1250 2. Z67 + 2700K = £663 3. X79 + 3930K = £1012 4. X79 + 3960X = £1365 Based on those numbers, for 12 cores you'll have: #1: 2500 #2: 1989 #3: 2024 #4: 2730 While #2 is slightly cheaper than #3, The difference is less than 2%, so having one system less would decidedly be an advantage. On the flip-side, #2 would be 9% faster, assuming linear speedup, but #3 being quad-channel memory while #2 is only dual-channel, #3 should atleast in theory have 33% higher memory-bandwidth (not 2x, since more cores means you'll need higher bandwidth just to keep the cores with enough bandwidth). While this extra bandwidth AFAIK isn't noticeable in WCG, atleast for now, it should be useful in other projects atleast, and possibly also with future WCG-projects. Compared to #3, #4 is out of the question since 35% more expensive for 3% higher clock-speed is in my opinion unacceptable. Similarly #1 is unacceptable with 24% more expensive for 4% higher clock-speed. So, either #2 or #3, the rest of the systems aren't interesting at their current prizes. Now, how you're managing to get so cheap 3930K compared to 2700K is to me a mystery, since you've managed to be less than 2% higher for 12 cores, while around here just the cpu's is 15% more expensive (for 12 cores) and mainboards is also more expensive. But anyway, since you are getting the 3930K so cheap, it's a good choise. As for there "soon" being released better cpu's, there is always "soon" to be released something better, so if you wait or buy now is up to you.  "I make so many mistakes. But then just think of all the mistakes I don't make, although I might." |
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mikey
Veteran Cruncher Joined: May 10, 2009 Post Count: 826 Status: Offline Project Badges: 
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I wondered if anyone could show me how they justify the purchase of 6 core cpu's because at this juncture I just don't see it. The advantage is in the Hyper Threading, or non HT! HT is using the same cpu core more than once thru on core manipulations. Using HT will only produce about 30% more work done than not using HT, so you are paying full price for something you will not be getting full use of. Is HT worth it, only if you already have it and/or use the pc for other things that WILL take advantage of it. For crunching it is not that helpful in the long run. YES a machine that is HT WILL produce more work than a non HT otherwise identical machine, but the cost is more too! I think you need to look more closely at the costs as you will NOT double your output thru HT!! Also SOME projects do not work very well at all when using HT, the additional work done can be as little as 5% or so. One other thing...each workunit requires x amount of memory, if you HT you will need to allow for that many more workunits and that much more memory or you lose more of the advantage and you will NEVER see anywhere close to the 30% number. Unfortunately it is not as simple as pure numbers of cores when getting new machines! And just to throw one more wrench into your plans...the motherboard can be a HUGE slowdown in the process too! If you spend $100 as opposed to $30 for a motherboard you will get ALOT more thruput and thus faster crunching and more workunits finished in less time. Buy cheap and go slow, buy better and go faster! SekeRob is also testing other ways of making the crunching happen faster and has had some very good results so far!   |
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OldChap
Veteran Cruncher UK Joined: Jun 5, 2009 Post Count: 978 Status: Offline Project Badges: 
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Just using a not particularly accurate rule of thumb calculation on pricing 3(4) separate rigs built solely for crunching I arrive at the following purchase prices... 1. X58 + 980x = ã1250 2. Z67 + 2700K = ã663 3. X79 + 3930K = ã1012 4. X79 + 3960X = ã1365 Based on those numbers, for 12 cores you'll have: #1: 2500 #2: 1989 #3: 2024 #4: 2730 While #2 is slightly cheaper than #3, The difference is less than 2%, so having one system less would decidedly be an advantage. On the flip-side, #2 would be 9% faster, assuming linear speedup, but #3 being quad-channel memory while #2 is only dual-channel, #3 should atleast in theory have 33% higher memory-bandwidth (not 2x, since more cores means you'll need higher bandwidth just to keep the cores with enough bandwidth). While this extra bandwidth AFAIK isn't noticeable in WCG, atleast for now, it should be useful in other projects atleast, and possibly also with future WCG-projects. Compared to #3, #4 is out of the question since 35% more expensive for 3% higher clock-speed is in my opinion unacceptable. Similarly #1 is unacceptable with 24% more expensive for 4% higher clock-speed. So, either #2 or #3, the rest of the systems aren't interesting at their current prizes. Now, how you're managing to get so cheap 3930K compared to 2700K is to me a mystery, since you've managed to be less than 2% higher for 12 cores, while around here just the cpu's is 15% more expensive (for 12 cores) and mainboards is also more expensive. But anyway, since you are getting the 3930K so cheap, it's a good choise. As for there "soon" being released better cpu's, there is always "soon" to be released something better, so if you wait or buy now is up to you. http://www.ebuyer.com/288239-intel-core-i7-39...-processor-bx80619i73930k £727.95 = MB , CPU and cooler deal http://www.ebuyer.com/319757-g-skill-16gb-4x4...-1-5v-f3-12800cl9q-16gbzl £68.31 =ram http://www.scan.co.uk/products/660w-seasonic-...eff-sli-crossfire-eps-12v £114.79 = PSU http://www.scan.co.uk/products/64gb-crucial-r...-write-95mb-s-new-version £79.97 = SSD This setup is about as cheap as I would go and still expect Longevity of parts This brings the cost down to £991.02 For the main stuff  |
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Bearcat
Master Cruncher USA Joined: Jan 6, 2007 Post Count: 2803 Status: Offline Project Badges:
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Careful on buying the 3930. Read this....
----------------------------------------http://www.techpowerup.com/mobile/156625/Inte...-stepping-in-January.html
Crunching for humanity since 2007!
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sk..
Master Cruncher http://s17.rimg.info/ccb5d62bd3e856cc0d1df9b0ee2f7f6a.gif Joined: Mar 22, 2007 Post Count: 2324 Status: Offline Project Badges:
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As for there "soon" being released better cpu's, there is always "soon" to be released something better, so if you wait or buy now is up to you. The significant feature of 32nm to 22nm is the dimensional change. The 980X, 2600K and 3830K are all 32nm. History repeatedly demonstrates that such a huge (45%) drop in dimensions brings a jump in relative performance. Ditto for the 40nm to 28nm jump; 60% reduction, and this time it's reportedly performance orientated, rather than feature orientated.So, wait. [Edit 1 times, last edit by skgiven at Jan 19, 2012 12:31:41 AM] |
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OldChap
Veteran Cruncher UK Joined: Jun 5, 2009 Post Count: 978 Status: Offline Project Badges:
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Wait? yes I see your point.
----------------------------------------Lets look at this many lesser rigs idea some more meanwhile.... Anyone point me at some E3-1230 results (or similar 1240 etc) |
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Hypernova
Master Cruncher Audaces Fortuna Juvat ! Vaud - Switzerland Joined: Dec 16, 2008 Post Count: 1908 Status: Offline Project Badges:
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Maybe you should wait until the first beta GPU test with HCC take place.
----------------------------------------Then the CPU choice may become irrelevant, but choice of a GPU will be the new game in town   |
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OldChap
Veteran Cruncher UK Joined: Jun 5, 2009 Post Count: 978 Status: Offline Project Badges:
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I am as ready as the next guy for that with a bunch of gpu's just waiting...but that will be just HCC (won't it?) and all the other projects will need some work too
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mikey
Veteran Cruncher Joined: May 10, 2009 Post Count: 826 Status: Offline Project Badges:
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I am as ready as the next guy for that with a bunch of gpu's just waiting...but that will be just HCC (won't it?) and all the other projects will need some work too Believe it or not I am now doing the same considering as you are! I got both money and gpu's for Christmas, my birthday was two days before so it is included, and am now thinking of getting a cheap AMD 6 core to replace one of my dual core pc's that is now crunching. Here in the US I can get one for about $400 from TigerDirect.com that is a build it yourself after they ship you the parts. I too want to do some cpu crunching for WCG, that is all there is right now, to move my numbers up a bit. BUT I do have some AMD gpu's that could work VERY nicely if WCG chooses to make it happen that way. I may just wait until they announce something and then either get the 6 core or get a good Nvidia gpu. Decisions, decisions!!! |
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