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World Community Grid Forums
Category: Completed Research
Forum: Help Conquer Cancer
Thread: HCC GPU APP HAS LAUNCHED. |
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Thread Status: Active Total posts in this thread: 363
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mikey
Veteran Cruncher Joined: May 10, 2009 Post Count: 821 Status: Offline Project Badges: 
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I thought it was amps, not volts, that kills. Wrong? My dad always told me it is like this, the volts provide the oomph behind the amps that kills you! SOOOOO the more voltage behind those amps the QUICKER it is the amps get thru you and the more damage it does. I amp will kill a horse, but with only 12 volts it make take a while, with 240 volts it is dead NOW!! MOST electricians die from the fall not the electricity, but it is the electricity that kicked them off their ladders etc.   |
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cjslman
Master Cruncher Mexico Joined: Nov 23, 2004 Post Count: 2082 Status: Offline Project Badges: 
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It's the amps that are dangerous. Think of it like a river... the volts are the water and the amps is the force/flow of the river. A lot of volts aren't necessarily dangerous... static electricity is an example of this... when you get shocked by static electricity (like with the damn shopping carts) you are exchanging thousands of volts through your body. On the other hand, only 60 mA of AC (that's 60 thousands of one amapere) can cause fibrillation.
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Movieman
Veteran Cruncher Joined: Sep 9, 2006 Post Count: 1042 Status: Offline |
No numbers but I'll tell you real world.
----------------------------------------Back in 1977 I made the mistake of wearing leather shoes, then putting my hand on a metal shelf in a grocery store. It was raining heavily that day and the carpet was wet. Unknown to me behind the shelving unit was a heavy duty extension cord that went to a coke machine and that cord had become frayed. Locked me solid to the shelf unit. I could see but not move. Luckily for me app 10 sec into this nightmare a VERY large young lady who looked to be 6' and over 220lbs realised what was happenning and came at me full steam and hit me with what one would describe as a football( US not European) block and knocked me 4 ft away and onto my backside. 30amp/220v line.. Something you don't forget and yes folks, it's the amperage that kills with a small assist from the voltage.  |
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dskagcommunity
Senior Cruncher Austria Joined: May 10, 2011 Post Count: 219 Status: Offline Project Badges: 
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Does anyone KNOW and tested, how much performance it costs on HCC when a card runs in a 4x slot? Best would be you have two same cards (6xxx or 7xxx) running and could tell me the difference or if there are generell problems with PCIe 4x and newer 7xxx cards. :) as example 10% difference should be no problem but i dont want to run with 50% loss or something ;)
----------------------------------------ppllzzzz i want 3 pieces of HD7770    to bring the thread back to topic :)---------------------------------------- [Edit 5 times, last edit by dskagcommunity at Oct 15, 2012 3:41:15 PM] |
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Jim1348
Veteran Cruncher USA Joined: Jul 13, 2009 Post Count: 1066 Status: Offline Project Badges:
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Does anyone KNOW and tested, how much performance it costs on HCC when a card runs in a 4x slot? Best would be you have two same cards (6xxx or 7xxx) running and could tell me the difference or if there are generell problems with PCIe 4x and newer 7xxx cards. :) as example 10% difference should be no problem but i dont want to run with 50% loss or something ;) ppllzzzz i want 3 pieces of HD7770 to bring the thread back to topic :)Good question. The short answer is "no", I don't. But I expect it won't be so bad, since this project alternates between CPU and GPU, with apparently not so much happening by both at the same time. But I have a 4x slot also and have been wondering whether to buy a third HD 7770 for it. (Note however that in general, for most OpenCL projects I am familiar with, a 4x slot would be a disaster, so what holds true here probably won't hold true everywhere.) Let me know. '  'EDIT: I would test it myself, but the slot is on a different PC from where the HD 7770s are, and I would have to mix Nvidia and AMD, which is not always a happy combination. So I would like to see some results first too. [Edit 2 times, last edit by Jim1348 at Oct 15, 2012 4:39:02 PM] |
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mmstick
Senior Cruncher Joined: Aug 19, 2010 Post Count: 151 Status: Offline Project Badges:
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You are better off buying a better graphics card and motherboard. My 180$ Sabertooth 990FX has one x16 slot, a x16/8 slot, a x8 slot, and a x4 slot, good enough for three 7970s. It would be far more efficient to get several 7970s, which have an OpenCL SP throughput of well over 4 TFlops, upwards to 5Tflops with a decent overclock, compared to a 7770 with only 1.3 Tflops. Having one strong card is better than having many weak cards.
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dskagcommunity
Senior Cruncher Austria Joined: May 10, 2011 Post Count: 219 Status: Offline Project Badges:
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But i looked at the existing charttable here. And two 7770 run 56 results per hour while a 7970 for the double price put out 40. The buget is limited too ;) and only two are for one machine, thee third is for my homeworkingpc ^^
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mmstick
Senior Cruncher Joined: Aug 19, 2010 Post Count: 151 Status: Offline Project Badges:
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But i looked at the existing charttable here. And two 7770 run 56 results per hour while a 7970 for the double price put out 40. The buget is limited too ;) and only two are for one machine, thee third is for my homeworkingpc ^^ The chart is not official, nor is it accurate. The creator of the chart does not own the hardware or tested what he listed. We have already seen that my 7950 is outputting over 100 work units per hour, and another user with is also getting similar results with his 7970 which is getting 120 work units per hour. if two 7770s are only outputting a measly 56 results per hour, that would make it a very poor choice, 5x slower than a 7950. There are two factors in how fast a work unit can complete, as I am using a 4Ghz FX-8120 I can service 8 threads simultaneously, each work unit will refuse to skip to a separate thread when running, so you need to have as many cores as you have work units, with nothing running on these, as well as to have fast frequencies for whenever the CPU portion of the work unit begins. If you do not have a good processor, your GPUs will remain mostly idle, doing nothing at all. Even at my 100 work units per hour, there is still a decent portion of time in which my graphics card is idle, so it would output faster if I clock my processor higher, or say, upgrade to that new FX-8350 coming out in the next week. [Edit 2 times, last edit by mmstick at Oct 15, 2012 5:05:16 PM] |
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Jim1348
Veteran Cruncher USA Joined: Jul 13, 2009 Post Count: 1066 Status: Offline Project Badges:
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You are better off buying a better graphics card and motherboard. My 180$ Sabertooth 990FX has one x16 slot, a x16/8 slot, a x8 slot, and a x4 slot, good enough for three 7970s. It would be far more efficient to get several 7970s, which have an OpenCL SP throughput of well over 4 TFlops, upwards to 5Tflops with a decent overclock, compared to a 7770 with only 1.3 Tflops. Having one strong card is better than having many weak cards. I could use more CPU power, but when I upgrade to Haswell next year, it will be better to run more tasks at once on a each HD 7770. I don't want to exceed a certain level of power (and fan noise) on this PC anyway; spreading out both on two cards probably will be better. And if you look at the GPU times given thus far, I am surprised at how little benefit you get from the higher-level cards; it may be because this project is optimized for a given number of shaders less than the maximum.EDIT: The latter point comes from my Folding experience; the early work units aren't as large and don't need as many shaders, as the later ones. And the lower-level cards actually run faster (e.g., 1 GHz on the HD 7770) than the higher-level cards, so you are better off with them at first. Maybe later the additional shaders will be worth it, but this project won't last more than a few months and probably won't change that. (However, don't hold me to any of this, we are still in the very early stages of finding out.) [Edit 2 times, last edit by Jim1348 at Oct 15, 2012 5:32:50 PM] |
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dskagcommunity
Senior Cruncher Austria Joined: May 10, 2011 Post Count: 219 Status: Offline Project Badges:
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But i must look at what my machines can handle. they are all still lga 775 c2d or low c2q cpu ( they all cheap upgraded from pentium4 slowly to get the max out of the older mainboards). There is no need for efficency on energy for much of my cards, they only should be cheap and run as much as possible results per days. When a single 7870 card for 200 euro is faster then two 7770 for 100 then i have no problem to buy the single card ;) but i dont think it is double fast in practical situation? In theoretical i know it has the twice gflop value ( only have little more than 300 euro to upgrade two machines, one of them running 24/7) or i only upgrade the 24/7 machine with a 7950 for 280 euro. But then i think i must use appinfo for 4 concurrent threads to use all 4 cores of a old q6600.
-------------------------------------------------------------------------------- [Edit 6 times, last edit by dskagcommunity at Oct 15, 2012 5:29:33 PM] |
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