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Voltage vs Heat; what nukes the cpu for good?

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October 16, 2009 2:21:44 AM

Hello,
I have a very simple question; is heat the only thing that can permanently kill a cpu? Or if I crank up the vcore (whilst cpu temp is moderate), could it alone nuke the cpu by pulling too much current?

Background; I've got a phenom II x3 720 with a very stable OC at 3.6GHz, memory at 1066, NB at 2600.
Now I got my hands on a second GeForce GTX 260 and it seems that CPU bottoms out at some games.
So I am looking into ways to get the clock up to 3.7-3.8 (I know that it might not be possible based on other people's level of success with 720).
The case is a Cooler Master HAF, and I got a Thermalright black 130 extreme heatsink with two 2k fans (yes, noisy...) so I never had any problems with cooling. The CPU is < 40C on max load.

Now, the 3.6 OC is at ~1.536V. I haven't had any success with 3.7 even at 1.58V, but I could try some more if necessary, but then I get back to the question at top; if I maintain temp <50C, could I damage the CPU with voltage?

Thanks
October 16, 2009 6:04:05 AM

too much voltage will shorten the cpu's lifespan but as long as you have good cooling it should be fine.

why dont you try the aod profiles. it works like the intel turbo feature. there is an article on tms hardware about it chech it out.

u can crank up the cpu to the max only when you are playing games rest of the time keep the cpu at its default clocks.


or there is a very good software called 'Phenom msr Tweaker' download it.

it works as a custom cool n quiet .
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October 16, 2009 6:37:09 AM

gunnarhx said:
Hello,
I have a very simple question; is heat the only thing that can permanently kill a cpu? Or if I crank up the vcore (whilst cpu temp is moderate), could it alone nuke the cpu by pulling too much current?

Background; I've got a phenom II x3 720 with a very stable OC at 3.6GHz, memory at 1066, NB at 2600.
Now I got my hands on a second GeForce GTX 260 and it seems that CPU bottoms out at some games.
So I am looking into ways to get the clock up to 3.7-3.8 (I know that it might not be possible based on other people's level of success with 720).
The case is a Cooler Master HAF, and I got a Thermalright black 130 extreme heatsink with two 2k fans (yes, noisy...) so I never had any problems with cooling. The CPU is < 40C on max load.

Now, the 3.6 OC is at ~1.536V. I haven't had any success with 3.7 even at 1.58V, but I could try some more if necessary, but then I get back to the question at top; if I maintain temp <50C, could I damage the CPU with voltage?

Thanks


Voltage = heat. You can remove the heat faster with better cooling, but you are still generating heat in the chip by over-volting it. Also, there is the minor problem with electro-migration, where gate material migrates from the +VDC side of the gate towards the GND side of the gate. This process will eventually kill that gate, and your CPU.
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October 16, 2009 6:55:31 AM

gunnarhx said:
could I damage the CPU with voltage?


Absolutely
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October 16, 2009 2:56:49 PM

Thanks for the responses.
Practically, it seems that you're saying that short term heat could be the killer, but even though temperature is under control, one will shorten the lifespan of the chip in the long run.
In my system, temperature looks to be under control, since I've got a lot of air moving in my case and dual heat sink fans.
I probably follow the suggestion to only bump up to max during games etc

Thanks again everybody
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October 17, 2009 12:30:08 AM

both heat and voltage can damage your cpu. Because it's easier to reduce the heat rather than voltage in an overclock. Most likely your cpu will die more quickly by the high voltage you're pumping in
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October 17, 2009 5:45:24 AM

I would say that voltage will kill it 10x faster than temps.

But as long as you keep the vcore within the cpu's specs, you should be pretty good.

I would say temp is the long term killer.
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October 17, 2009 10:13:37 AM

overshocked said:
I would say that voltage will kill it 10x faster than temps.

But as long as you keep the vcore in intels specs, you should be pretty good.

I would say temp is the long term killer.



Good explanation !
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October 17, 2009 10:28:06 AM

yes but for every 10c cooler your chip is it doubles its life span so i rape my cpu's with high voltage but reduce the temps by like 80-90c to make up for the life span losses :D  my e8600 has ran for a year as my main oc with 1.47vcore and have benched it upto 1.68v :D 
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October 17, 2009 12:20:12 PM

overshocked said:
I would say that voltage will kill it 10x faster than temps.

But as long as you keep the vcore in intels specs, you should be pretty good.

I would say temp is the long term killer.

You mean amd's specs lol
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October 17, 2009 12:45:04 PM

CPUs specs would be better
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October 17, 2009 10:24:06 PM

Thanks for the continued info.

It seems that the prevailing opinion is that both voltage and temp will shorten the life expectancy of the CPU. So preferably keep the vcore within spec ( or close at least ) and keep a good look at the temp ( I guess, as low as possible).

In my case, temp has never been a problem, so I will try to keep the voltage as low as I can for the frequency I want.

BTW, since we are on the topic; for a non-professional OC'er, who just try to bump up the speed to a 'respectable' level for purpose of video encoding, games etc. And assume that this person is challenging the specs for 1) voltage and 2) temp. What would the life expectancy be for both intel and amd chips?
Does anyone have experience in terms of years/months before the chip finally gives in?? Would be interesting to know...

Thanks
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October 17, 2009 11:03:02 PM

ubernoobie said:
You mean amd's specs lol


fixed lol
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October 18, 2009 10:14:52 PM

if you keep both the vcore and temps below the cpu's specs then you can guarantee it will last 2 years or your money back :D 
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October 19, 2009 3:09:44 AM

gunnarhx,

I realize this is an AMD thread, however, the following very excellent AnandTech article explains processor degradation, which addresses the effects of excessive voltage and temperature. Although it concerns Intel, the principals also apply to AMD: - http://anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3...

4ryan6,

Please excuse the slightly off-topic detour for a moment . While I agree with overshocked's statement, I would also like to take issue with it.

overshocked said:
I would say that voltage will kill it 10x faster than temps.

But as long as you keep the vcore within the cpu's specs, you should be pretty good.

I would say temp is the long term killer.
overshocked,

I'm glad that you've commented on this point, because I've had a burning question to ask since you rolled out your Core i7 Overclocking Guide: Don't you think it's irresponsible to recommend to our readers temperatures and core voltages which exceed specifications?

From your Guide:

Quote:
When at a full load the core i7 should not exceed 75c, 80c MAX.
From Intel's Processor Spec Finder - http://processorfinder.intel.com/List.aspx?ParentRadio=...

All Core i7 9xx variants:
68c Tcase Max (CPU temperature)

Since Intel's Thermal Specification is Tcase Max, add 5c to find the corresponding Tjunction (Core temperature) value, which is 73c, not "75c, 80c MAX". See the following Intel engineering document - http://arxiv.org/ftp/arxiv/papers/0709/0709.1861.pdf

From your Guide:

Quote:
... max safe voltage for this chip is 1.375v
From Intel's Processor Spec Finder - http://processorfinder.intel.com/List.aspx?ParentRadio=...

All Core i7 9xx variants:
VID Voltage Range .80V-1.375V

Quote:
... MAX voltage is 1.55 that means that up until that number your risk of damaging the chip is not that high...
I have never read any such specification in hundreds of pages of Intel Core i7 documents and papers. Perhaps I missed it? Would you care to share with us where Intel provides this information?

As I've responded to threads and provided help to our Forum Members throughout the past 3+ years, I'm always mindful that most consider the money they have wrapped up in their rigs as hard earned. Consequently, I've been very careful to not make any suggestions or recommendations to our readers in threads, or in my Core i7 and Core 2 Temperature Guide, which exceed manufacturer's specifications, or could result in someone toasting their transistors.

Aren't you contradicting yourself here in this thread? Would you consider correcting your Guide?

Respectfully,

Comp :sol: 
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October 19, 2009 6:00:44 AM

CompuTronix said:
gunnarhx,

I realize this is an AMD thread, however, the following very excellent AnandTech article explains processor degradation, which addresses the effects of excessive voltage and temperature. Although it concerns Intel, the principals also apply to AMD: - http://anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3...

4ryan6,

Please excuse the slightly off-topic detour for a moment . While I agree with overshocked's statement, I would also like to take issue with it.

overshocked,

I'm glad that you've commented on this point, because I've had a burning question to ask since you rolled out your Core i7 Overclocking Guide: Don't you think it's irresponsible to recommend to our readers temperatures and core voltages which exceed specifications?

From your Guide:

From Intel's Processor Spec Finder - http://processorfinder.intel.com/List.aspx?ParentRadio=...

All Core i7 9xx variants:
68c Tcase Max (CPU temperature)

Since Intel's Thermal Specification is Tcase Max, add 5c to find the corresponding Tjunction (Core temperature) value, which is 73c, not "75c, 80c MAX". See the following Intel engineering document - http://arxiv.org/ftp/arxiv/papers/0709/0709.1861.pdf

From your Guide:

From Intel's Processor Spec Finder - http://processorfinder.intel.com/List.aspx?ParentRadio=...

All Core i7 9xx variants:
VID Voltage Range .80V-1.375V

I have never read any such specification in hundreds of pages of Intel Core i7 documents and papers. Perhaps I missed it? Would you care to share with us where Intel provides this information?

As I've responded to threads and provided help to our Forum Members throughout the past 3+ years, I'm always mindful that most consider the money they have wrapped up in their rigs as hard earned. Consequently, I've been very careful to not make any suggestions or recommendations to our readers in threads, or in my Core i7 and Core 2 Temperature Guide, which exceed manufacturer's specifications, or could result in someone toasting their transistors.

Aren't you contradicting yourself here in this thread? Would you consider correcting your Guide?

Respectfully,

Comp :sol: 


No offense comp, but i think there is to much hype over "specs".....

Lets give this a little thought, overclocking is out of spec to begin with. I encourage people to rock on, and crank up the voltage a little out of spec [:lectrocrew:6] . I dont think its irresponsible at all.

I have run cpu's into the dirt, pushing 1.9 vcore and going down to -120c. Witch are both WAAAYYYY out of spec. and they keep on rocking.

24/7 i like to keep it at -45c and with 1.6vcore. I have never had a hiccup.

These users (the ones that will overclock) traditionally are looking to update there hardware within 3 years. Wich is about 1/10 of how long intel says a chip will run if its in spec.


Id say to hell with intels spec sheet. [:jaydeejohn:4] Overclocking is awesome and have some fun with it.
[:thegreatgrapeape:3]

Cheers
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October 19, 2009 6:03:00 AM

I don't argue that having one's guides be accurate is important. My comment is in regards to 73*C vs 80*C core temps. I agree that the Intel spec of 73*C should be stated. Then I have no problem with offering a personal opinion that 80*C for full load is still within a personal comfort range. And then I personally would like the reasoning for that comfort range of 80*C.

It just so happens that my 4.0 overclock took me to 80-81*C during testing. Certainly I was uncomfortable and decided that 4 hours of Prime95 at these temps was enough "stability" for me (along with 1 hour of OCCT, 50 passes of Intel Burn Test and 3 passes of memtest86+). I have read more than one site which has stated 80*C is ok, without specifics to back it up. I personally am comfortable knowing that I will never be running at 80*C during my normal computing and hopefully, never again. It is ironic that my testing alone subjects my chip to the worst beating it will take. But I justify this for the sake of trust in the systems "stability".

The fact that Intel claims that the core i7 920 will start to shut down at 100*C, and the fact that I haven't seen reports of fried chips from 80*C use, I made my own deductions. If there is evidence to the contrary, someone please chime in.
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October 19, 2009 6:40:53 AM

peacemaker- said:
I don't argue that having one's guides be accurate is important. My comment is in regards to 73*C vs 80*C core temps. I agree that the Intel spec of 73*C should be stated. Then I have no problem with offering a personal opinion that 80*C for full load is still within a personal comfort range. And then I personally would like the reasoning for that comfort range of 80*C.

It just so happens that my 4.0 overclock took me to 80-81*C during testing. Certainly I was uncomfortable and decided that 4 hours of Prime95 at these temps was enough "stability" for me (along with 1 hour of OCCT, 50 passes of Intel Burn Test and 3 passes of memtest86+). I have read more than one site which has stated 80*C is ok, without specifics to back it up. I personally am comfortable knowing that I will never be running at 80*C during my normal computing and hopefully, never again. It is ironic that my testing alone subjects my chip to the worst beating it will take. But I justify this for the sake of trust in the systems "stability".

The fact that Intel claims that the core i7 920 will start to shut down at 100*C, and the fact that I haven't seen reports of fried chips from 80*C use, I made my own deductions. If there is evidence to the contrary, someone please chime in.



Yeah man, for 100% load it is fine to go over intel specs.

Hence why i state that the absolute max is 80c.

On extreme air benching i have gone up to 107c with the i7, and it doesnt shut down. Im sure it was scaling back though. [:mousemonkey:4]
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October 19, 2009 7:36:09 AM

75C scares me a little. With the warm weather and lack of AC, I had to back off my overclock.
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October 19, 2009 3:06:16 PM

overshocked said:
Id say to hell with intels spec sheet. [:jaydeejohn:4] Overclocking is awesome and have some fun with it.[:thegreatgrapeape:3]

overshocked,

I'm all for fun, but that's quite a flippant attitude when it involves other people's money. Suit yourself; I still think it's irresponsible. Regardless, you haven't answered my question concerning your claim that "The MAX voltage is 1.55". I find it difficult to believe that you haven't encountered any processor degradation while running "cpu's into the dirt"... or have you?

So, where did you come up with 1.55?

Comp :sol: 
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October 19, 2009 3:56:12 PM

CompuTronix said:
overshocked,

I'm all for fun, but that's quite a flippant attitude when it involves other people's money. Suit yourself; I still think it's irresponsible. Regardless, you haven't answered my question concerning your claim that "The MAX voltage is 1.55". I find it difficult to believe that you haven't encountered any processor degradation while running "cpu's into the dirt"... or have you?

So, where did you come up with 1.55?

Comp :sol: 


I know youd love for me to say that I pulled it out of my arse, but nope.

Strait from the DATA sheet itself.


Processor Absolute Minimum and Maximum Ratings



Symbol------------------Parrameter--------------------------------- max
VCC-----Processor Core voltage with respect to VSS------- 1.55 V

Happy? [:lectrocrew:2]
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October 19, 2009 4:34:55 PM

1.55 it is indeed. Sir, I stand corrected. Shame on me for not recalling my notes more carefully.

However, in all fairness, and to offer perspective, the following is for everone's benefit: Intel® Core™ i7 Processor Extreme Edition and Intel® Core™ i7 Processor, Datasheet, Volume 1 - http://download.intel.com/design/processor/datashts/320...


"2.10 Absolute Maximum and Minimum Ratings

Table 2-6 specifies absolute maximum and minimum ratings, which lie outside the functional limits of the processor. Only within specified operation limits can functionality and long-term reliability be expected.

At conditions outside functional operation condition limits, but within absolute maximum and minimum ratings, neither functionality nor long-term reliability can be expected. If a device is returned to conditions within functional operation limits after having been subjected to conditions outside these limits, but within the absolute maximum and minimum ratings, the device may be functional, but with its lifetime degraded depending on exposure to conditions exceeding the functional operation condition limits.

At conditions exceeding absolute maximum and minimum ratings, neither functionality nor long-term reliability can be expected. Moreover, if a device is subjected to these conditions for any length of time then, when returned to conditions within the functional operating condition limits, it will either not function or its reliability will be severely degraded."


Have you encountered any processor degradation, or are Intel's engineers mistaken?
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October 19, 2009 4:40:12 PM

Im sure i have but i have been running my cpu's for years like this and nothing noticable has happend yet....
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October 19, 2009 6:01:12 PM

With respect to the title of this thread - Voltage vs Heat; what nukes the cpu for good?, and with respect to your previous statment:
overshocked said:
I would say that voltage will kill it 10x faster than temps.

But as long as you keep the vcore within the cpu's specs, you should be pretty good.

I would say temp is the long term killer.
I would say that processor degradation is an undeniable issue in 45 nanometer technology, which shouldn't be dismissed, and will become more pronounced as die-shrinks evolve. The AnandTech article I posted above - http://anandtech.com/cpuchipsets/i [...] i=3251&p=6 - offers a clear explanation. If you follow the Real Temp thread at ExtremeSystems, a very astute Forum Member, rge, who has assisted Real Temp's developer, Kevin Glynn, with much of his research, has documented processor degradation due to overvolting. This is certainly not an isolated instance.

Additionally, an anonymous Intel engineer stated on the Real Temp thread that the VID Voltage Range value shown in the Processor Spec Finder should not be exceeded, because there is very little upward tolerance before degradation occurs.

My point is that since Intel clearly states that operating a processor at "Absolute Maximum" will result in degradation, and it's been documented by others, including myself, do you really think it's wise to suggest that it's OK to ramp the Vcore up from 1.375 to 1.55? That's a 12.73% increase. Don't you think that's pushing toward the extreme for the novice overclocker who might not understand the potential consequences?
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October 19, 2009 6:14:13 PM

Of course every di shrink is more proned to degregation than the size before.

But be that as it may, I did (and continue) to suggest that people have fun with there chips. I usually warn people and say that degradation does occur.

At that point i bestowe the resposobility apon them to do more research and find out how much is to much. It is beyond the outlook of my guide to tell them.

Why is this beyond the outlook of my guide?
Becuase there is some risk involved in overclocking at all, they should do what they feel safe doing.
Hence why i dont call my guide (and nor should anyone call their guide) the bible of overclocking. It is simply an "i7 overclocking guide".

Personally I like to put myself under potential "risk" and slap a phase change on my system or an LN2 pot and crank up the voltage all the way.

The outlook of my guide however IS to show what I have expierienced as well as show HOW to overclock. [:lectrocrew:6]
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October 19, 2009 6:49:57 PM

overshocked said:
Of course every di shrink is more proned to degregation that the size before.

But be that as it may, I did (and continue) to suggest that people have fun with there chips.[:lectrocrew:6]
I couldn't agree more. These processors are such excellent overclockers, it's almost a sin to leave them at stock! :D 

As for the rest of it; I'm an engineer, so my approach is more conservative, :??:  while your approach is more aggressive. :kaola:  Regardless, I can certainly meet you half-way, and just agree to disagree. :lol: 

See you around the Forums,

Comp :sol: 
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October 20, 2009 8:15:00 PM

CompuTronix said:

As for the rest of it; I'm an engineer, so my approach is more conservative, :??:  while your approach is more aggressive. :kaola:  Regardless, I can certainly meet you half-way, and just agree to disagree. :lol: 


Agreed...

Are you a mechanical engineer?

CompuTronix said:
I couldn't agree more. These processors are such excellent overclockers, it's almost a sin to leave them at stock!


Definetly.... lol, reminds me of a maximum pc article... [:jaydeejohn:4]

"There’s actually a state law that says a 920 has to be overclocked, so we obliged—all the way to 3.66GHz."

http://www.maximumpc.com/article/features/dream_machine...
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October 20, 2009 10:12:49 PM

overshocked said:
Are you a mechanical engineer?
As you might guess from my username, electronics. :) 

Since the R&D environment never appealed to me, I've always enjoyed hands-on as a field engineer, but I'm primarily a troubleshooter. Although I'm not a thermodynamics engineer, my background is in marine, aviation and medical electronics with the Navy, General Electric and Philips. I'm a systems specialist in MRI and CAT scan, both of which are $1M+ systems that utilize air and liquid cooled diverse electronics hardware, and are computer driven networked systems.

I work with Silicon Graphics, Sun Microsystems and multi-vendor Xeon PC's, which are SCSI / Unix based systems. For my work here at Tom's, I conduct much of my research and testing on different platform/processor/cooler configurations at a local PC shop. I'm a Navy veteran, FAA licensed pilot, USCG licensed captain and master mariner. I live aboard my sailboat in Fort Lauderdale, from where I cruise the Florida Keys and Bahamas.

"Wind @ 12 knots, cruising trim, auto-pilot, Jimmy Buffett, and cold beer!" :love: 

Regardless, the common thread is that we're both here to help our readers, so on this point, we're precisely on the same page. :D 

Comp :sol: 
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October 21, 2009 2:14:44 AM

CompuTronix,

Please let me know if you wish me to start a new thread with this. It seem related enough...

I am reading the temperature guide in your signature (I believe you wrote it) because I have

Tjunction Load = Tcase Load + 13c (80c = 67c + 13c)
Tjunction Idle = Tcase Idle + 10c (37c = 27c+ 10c)

My ambient is currently 19c but the idle delta is true at 22c as well.

Based on your guide my take is that either Tjunction or Tcase is inaccurate because the difference should only be 5c. Do I understand correctly?

I have a p6t deluxe v2 and am currently overclocked to 4.0GHz using 21*191 at vcore = 1.25v and vtt = 1.25v. I am hitting 80c using Prime95 small FFT and this seems high with 1.25v vcore. I am trying to figure out if the problem is:
1) case (4 Noctua 120mm fans) - seems like this should be enough - the mb temp is 35c according to speedfan
2) cpu cooler (Noctua NH-U12P SE2 with dual fans) - need to reseat or fans not enough for the task
3) inaccurate temps
4) luck of the draw
5) Have I missed anything?

I have not yet run your calibration. I want to make sure I fully understand what I am about to undertake, considering it is a fair amount of work. And I want to make sure it helps me solve the problem of 80c load.


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October 21, 2009 2:35:59 AM

peacemaker- said:
CompuTronix,

Please let me know if you wish me to start a new thread with this. It seem related enough... Based on your guide my take is that either Tjunction or Tcase is inaccurate because the difference should only be 5c. Do I understand correctly?
I've hijacked gunnarhx's AMD thread, for which I apologize. Yes, you understand correctly. Just open a new Intel thread, then send me a Private Message (PM) with the link, and I'll be glad to help you. Please be patient if I don't respond in a timely fashion, since I must check for all thread/PM notifications manually, as I haven't received any email notifications since September 24th due a Forum bug.

Comp :sol: 
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October 21, 2009 3:44:25 AM

CompuTronix,
No reason to apologize. The link you provided to anantech.com directly discussed the question I asked, even though they mainly talked about intel cpus. One could assume that the same reasoning could be applied to other advanced silicon processes.
Thanks for the input everyone.
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October 21, 2009 4:08:55 AM

Glad we could help! :sol: 
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October 21, 2009 4:37:43 PM

CompuTronix said:
As you might guess from my username, electronics. :) 

Since the R&D environment never appealed to me, I've always enjoyed hands-on as a field engineer, but I'm primarily a troubleshooter. Although I'm not a thermodynamics engineer, my background is in marine, aviation and medical electronics with the Navy, General Electric and Philips. I'm a systems specialist in MRI and CAT scan, both of which are $1M+ systems that utilize air and liquid cooled diverse electronics hardware, and are computer driven networked systems.

I work with Silicon Graphics, Sun Microsystems and multi-vendor Xeon PC's, which are SCSI / Unix based systems. For my work here at Tom's, I conduct much of my research and testing on different platform/processor/cooler configurations at a local PC shop. I'm a Navy veteran, FAA licensed pilot, USCG licensed captain and master mariner. I live aboard my sailboat in Fort Lauderdale, from where I cruise the Florida Keys and Bahamas.

"Wind @ 12 knots, cruising trim, auto-pilot, Jimmy Buffett, and cold beer!" :love: 

Regardless, the common thread is that we're both here to help our readers, so on this point, we're precisely on the same page. :D 

Comp :sol: 


Awesome! You work with cat scans!

Can you get free LHE4? [:lectrocrew:6]
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October 21, 2009 7:58:11 PM

overshocked said:
Awesome! You work with cat scans!

Can you get free LHE4?[:lectrocrew:6]
Sorry, but no. CAT (Computed Axial Tomography) or CT scanners use a rotating 150,000 volt X-Ray tube.

Conventional high-field MRI (Magnetic Resonance Imaging) uses a powerful superconductive magnet, which has a 1,000 to 2,000 liter vessel of LHe (Liquid Helium) to sustain the magnetic field. As the LHe boils off at a rate of up to 0.5% per day, certain magnet types must be refilled several times per year. The rate of boil off depends upon the efficiency of a "cold head" or "shield cooler" that's in contact with the magnet's inner thermal shields, which extracts heat from the magnet with cold gaseous helium, which is recirculated through a cryogenic compressor, which is cooled by a chilled water unit, which finally transfers heat to the outside atmosphere, all of which runs 24/7.

Since the boiling point of LHe is -268.93c (-452.074f), which is only ~4.2c (~7.6f) above absolute zero, which is -273.15 (-459.67f), it vaporizes on contact with any atmosphere, so it won't collect in an open container like liquid nitrogen (Ln), :(  which has a relatively warm boiling point at -195.80c (-320.44f).

When pressure-transferring LHe from it's vacuum insulated "dewar", through a specially designed high-efficiency vacuum line, into the already cold magnet vessel, only an 80% transfer is achieved, so 1 out of every 5 liters boils off just in the transfer. Even with a cryogen contract, the cost of keeping an MRI superconductive magnet cold can exceed $1,200 per month just for LHe, not including service and periodic replacement of cryogenic parts. So, considering that LHe requires specialized equipment for handling, and can exceed ~ $8.50/liter, compared with Ln at ~ $0.25/liter, it's not very practical for overclocking experiments. Sorry. :( 

Comp :sol: 
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October 21, 2009 10:59:11 PM

all good computronix apart from LHe does stay in liquid form in a dewar, overclockers have used it before on the new phenomII chips as they dont have a cold bug.
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October 21, 2009 11:35:03 PM

richardscott said:
... LHe does stay in liquid form in a dewar...
I'm well aware of that, since I've performed LHe and LN cryofills for many years. As I mentioned above, "... it vaporizes on contact with any atmosphere, so it won't collect in an open container like liquid nitrogen ..." I also mentioned "When pressure-transferring LHe from it's vacuum insulated "dewar ..."

If overshocked has access to the proper equipment, can obtain LHe, knows how to handle it safely, and has the money to blow, then hopefully he'll share his results with us. :D 
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October 22, 2009 5:49:23 AM

CompuTronix said:
I'm well aware of that, since I've performed LHe and LN cryofills for many years. As I mentioned above, "... it vaporizes on contact with any atmosphere, so it won't collect in an open container like liquid nitrogen ..." I also mentioned "When pressure-transferring LHe from it's vacuum insulated "dewar ..."

If overshocked has access to the proper equipment, can obtain LHe, knows how to handle it safely, and has the money to blow, then hopefully he'll share his results with us. :D 


OH trust me, ive already inquired about prices of lhe.

The prices were kinda vague but i got quoted on 60l for $400.... Not worth it when the ln2 price here is $0.69/l

Any way, you would need about 60l to do an hour run.


Maybe some day i can get some guys together to split the lhe.[:lectrocrew:6]


I dont have access to the equipment for a lhe run but im maybe if i was lucky, UT might let me use their lab. I only have the equipment for ln2 right now.
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October 22, 2009 5:50:52 AM

ANy chances you live in texas comp?
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a b K Overclocking
October 22, 2009 6:25:50 AM

No, I'm in Fort Lauderdale, however, I do occasionally travel to Dallas and Houston on business.
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October 22, 2009 6:35:42 AM

Hmmm thats to bad.... id love to see what you could do with some ln2 and an i7.

Or an i9 if i can get my hands on an early sample.
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October 22, 2009 1:17:19 PM

richardscott said:
overshocked 500l of LHe only give you 90 mins of overclocking lol.


That would be 90 mins of ecstasy for overshocked :lol: 
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October 22, 2009 4:11:37 PM

richardscott said:
overshocked 500l of LHe only give you 90 mins of overclocking lol.

http://www.youtube.com/watch?v=wB0JodKgZ0A

http://www.youtube.com/watch?v=2Z6UJbwxBZI&feature=rela...

you need to insulate the liquid helium with liquid nitrogen to keep it in a dewar, but the transfer efficiency would be lower than 50%



Meh, you can get soooo much more time with the precious helium if you do insulate it with ln2.

500l would cost way to much though. We need someone with connections.

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October 22, 2009 4:14:01 PM

4Ryan6 said:
That would be 90 mins of ecstasy for overshocked :lol: 



HHAHHAHAHA

Ryan, you have no idea how much fun that would be for me.

If i can get one of those i9 early release chips and 500l of helium. Shammy said that his i9 chip coldbugged at -190 (cant remember exact number).

If thats true than one of these chips will prolly coldbug at -210. [:lectrocrew:6] [:lectrocrew:6]
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October 22, 2009 8:55:53 PM

overshocked said:
Meh, you can get soooo much more time with the precious helium if you do insulate it with ln2.

500l would cost way to much though. We need someone with connections.



not really as you have to take the latent heat into consideration, as helium only has 4 electrons in a closed outer shell it doesn't have very strong inter molecular bonds it will vapourise easily.

you need 10x the amount of LHe compared to LN2.

http://en.wikipedia.org/wiki/Latent_heat
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October 23, 2009 2:09:46 AM

HAHA, Thanks dude.

That is actually helpful to me because a friend on ocn was saying how he would only need 2-3l of lhe to get a bit of overclocking time.

I was trying to tell him how he would need 60l of lhe for that. He didnt believe me. LOL
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a b K Overclocking
October 23, 2009 12:12:44 PM

60l would give less than 10 mins plus how ever much he needs for the cooldown so for a min id say 200l
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October 23, 2009 6:04:19 PM

Geeze.... so i guess it wont ever be in the hands of a non-sponsored person then.
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a b K Overclocking
October 23, 2009 7:02:14 PM

nope, tbh LN2 under vacuum can probably reach like -210 to -220
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October 23, 2009 7:07:46 PM

The Periodic Table of Elements shows the melting point for Nitrogen at -209.86c, and the boiling point at -195.80c.
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