Mersenne Digest Saturday, March 3 2001 Volume 01 : Number 822 ---------------------------------------------------------------------- Date: Tue, 27 Feb 2001 19:55:15 -0000 From: "Brian J. Beesley" <[EMAIL PROTECTED]> Subject: Re: Mersenne: CPU operating temps On 27 Feb 2001, at 8:56, Brian Last-Name wrote: > I am running a Cyrix 233 OC'ed to ~266 by a > faster bus speed. I cannot touch the processor heat sink for more than two > or three seconds without pain, and the voltage regulators are even hotter. > It has been running trial testing for over two years without many "issues". Older designs are more resistant to overheating because there is a lower probability of electrons released by excess temperature from making their way through to an adjoining circuit. The circuits are in much closer proximity with modern high-density designs. People's tolerance to heat pain does vary; because of thermal conductivity, handling hot metal isn't easy, most people will begin to register pain at ~50C (120F). At ~70C (156F) few people will be able to hold hot metal for more than a second. A few degrees above that and touching for more than a split second will cause obvious burns. Casting my mind back a few years, I seem to remember that Cyrix processors were noted for hot running. Voltage regs running hot are fine. They're not subject to data corruption caused by overheating. Either they work, or they cook themselves to death. > I havent even been using frag tape or heat conducting grease. These are more neccessary with newer designs, because their heat ouput per unit area is much greater than with old designs, and it's therefore more neccessary to conduct excess heat away from the chip efficiently. > What is the maximum operating temperature (recommended) for a processor? > I will measure the temp. at the bottom of the heat sink while operating. Technically you're looking at around 130C at the hottest point inside the circuitry of the working chip. There's _no way_ to measure that, without more access to the chip than a working processor usually has available, and even then without specialist equipment like a pyrometer. The position of the temp sensor depends on the processor cartridge and/or motherboard design. Slotted Intel PII/PIII have the thermistor mounted on the small board inside the cartridge; slotted Athlons don't come with a thermistor, if you want that option you have to mount one yourself, the only place to do it is to wedge the thermistor between the fins of the heatsink. Socketed designs usually have the thermistor mounted in the "hole" in the CPU socket, immediately under the processor itself. Obviously these different mounting methods will all read "low" compared with the critical temperature internal to the chip, but how low depends on many factors. Therefore it isn't possible to give a maximum temperature without knowing several other variables. If your system has been running for two years, still passes the Prime95/mprime self test & isn't either crashing frequently or producing error messages frequently when Prime95/mprime is running, it's not actually overheating. Don't worry about it. Start worrying if and only if you start seeing symptoms which could possibly be attributed to overheating. My standard procedure is, some time around July when the weather is warm, to remove all the "SelfTest" lines from local.ini. Prime95/mprime will then re-run the self-test next time it needs to use each FFT run length. If overheating is going to hit you, it's _much_ more likely to be a problem when the system is operated in an unusually warm environment. Regards Brian Beesley _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Tue, 27 Feb 2001 14:55:25 -0600 From: "Jeramy Ross" <[EMAIL PROTECTED]> Subject: Re: Mersenne: CPU operating temps First, it is quite normal for a processor to run hot enough to prevent one from being able to touch it for over 2 secs or so. When Intel first introduced the PII, a common joke in computer science circles was that Intel had successfully marketed the most expensive egg frier to date ;-) To find the specific temp info you need to go to http://www.cyrix.com and look up your processor. Alot of manufacturers produce several versions of a specific processor that have different heat tolerances. I know that AMD K6-2's had a copule different versions per clock speed (atleast at 500MHz) that had about a 10 degree C difference in their tolerance. If I remember right, the average safe (or sometimes called normal) max. is arround 70C which is arround 158F, BUT this varies alot! Secondly, One *should* use some sort of thermally conductively compound between your processor and heatsink. The truth of the matter is that the joint made between the bare heat disapator on the processor (Using the Socket7 type example since we are talking about the Cyrix MII 233 processor) and your heat sink is a very poor conductor of heat. The use of the thermal conductor compound remedies this. Again.. check http://www.cyrix.com for the technical documents that will give you the thermal mesurements and such that will help you in designing a proper cooling arrangement to keep your processor running. REMEMBER that since you have OC'd your processor you need to be esp. careful and factor that in to the equation. Hope this helps, Jeramy - ----- Original Message ----- From: "Brian Last-Name" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, February 27, 2001 7:56 AM Subject: Mersenne: CPU operating temps > Seeing all of this information on spontaneous rebooting, I am beginnin to > wonder why my computer works. I am running a Cyrix 233 OC'ed to ~266 by a > faster bus speed. I cannot touch the processor heat sink for more than two > or three seconds without pain, and the voltage regulators are even hotter. > It has been running trial testing for over two years without many "issues". > I havent even been using frag tape or heat conducting grease. > What is the maximum operating temperature (recommended) for a processor? > I will measure the temp. at the bottom of the heat sink while operating. > > Brian _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Tue, 27 Feb 2001 13:19:05 -0800 (PST) From: John R Pierce <[EMAIL PROTECTED]> Subject: Re: Mersenne: CPU operating temps > Secondly, One *should* use some sort of thermally conductively compound > between your processor and heatsink. The truth of the matter is that the > joint made between the bare heat disapator on the processor (Using the > Socket7 type example since we are talking about the Cyrix MII 233 processor) > and your heat sink is a very poor conductor of heat. The use of the > thermal conductor compound remedies this. Again.. check > http://www.cyrix.com for the technical documents that will give you the > thermal mesurements and such that will help you in designing a proper > cooling arrangement to keep your processor running. thirdly, and I'm amazed folks don't consider this sometimes... No matter HOW good your CPU heat sink is, if the chassis isn't getting enough airflow in the vicinity of that heatsink, it will have a MUCH harder time keeping the CPU cool. Adding an extra case fan to move fresh air past the general vicinity of the CPU, and paying attention to ribbon cable routing so it doesn't act as a barrier to airflow can make a HUGE difference. - -jrp _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Tue, 27 Feb 2001 15:22:52 -0600 From: "Jeramy Ross" <[EMAIL PROTECTED]> Subject: Re: Mersenne: CPU operating temps An extra case fan is always a good idea and helps more than just your processor. Due to the narrow nature of the question I didn't bring up this point, but it is always a good point to bring up! Thanks John! Jeramy - ----- Original Message ----- From: "John R Pierce" <[EMAIL PROTECTED]> > > thirdly, and I'm amazed folks don't consider this sometimes... No matter > HOW good your CPU heat sink is, if the chassis isn't getting enough airflow > in the vicinity of that heatsink, it will have a MUCH harder time keeping > the CPU cool. Adding an extra case fan to move fresh air past the general > vicinity of the CPU, and paying attention to ribbon cable routing so it > doesn't act as a barrier to airflow can make a HUGE difference. > > -jrp > > _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Tue, 27 Feb 2001 15:33:50 -0600 From: "Jeramy Ross" <[EMAIL PROTECTED]> Subject: Re: Mersenne: CPU operating temps - ----- Original Message ----- From: "Brian J. Beesley" <[EMAIL PROTECTED]> > Older designs are more resistant to overheating because there is a > lower probability of electrons released by excess temperature from > making their way through to an adjoining circuit. The circuits are in > much closer proximity with modern high-density designs. Electron boil-over is only one aspect to mention in this problem. While older designs are more resistant to that aspect of overheating, older designs tend to have just as much of a problem to failure due to excessive heat as newer ones. One needs to look at all aspects of damage due to overheating. > Voltage regs running hot are fine. They're not subject to data > corruption caused by overheating. Either they work, or they cook > themselves to death. These aren't much to worry about, but that is a fine line that you are walking here. They either work or cook themselves to death. The fact that the processor is OC'd may be playing a part here, and there might be more of a strain on these regulators than the motherboard designer planned for which may cause a problem in the future, AND if they do fail they tend to take out quite a few other components on your motherboard with them..INCLUDING your processor. Their health is a very important aspect. > These are more neccessary with newer designs, because their heat > ouput per unit area is much greater than with old designs, and it's > therefore more neccessary to conduct excess heat away from the chip > efficiently. The processor at issue here is a older design, BUT new enough to merit the conductive grease or tape. ESP. when the processor is OC'd. > If your system has been running for two years, still passes the > Prime95/mprime self test & isn't either crashing frequently or > producing error messages frequently when Prime95/mprime is running, > it's not actually overheating. Don't worry about it. Start worrying > if and only if you start seeing symptoms which could possibly be > attributed to overheating. Well this is one way of looking at it. Not to get harsh, but most people I know prefer to keep things in good working order and PREVENT such problems...not simply wait until they occur. Always better to be safe than sorry... and when it comes to ones computer...the sorry bit can get to be quite expensive. Jeramy _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Wed, 28 Feb 2001 07:29:16 -0000 From: "Brian J. Beesley" <[EMAIL PROTECTED]> Subject: Re: Mersenne: CPU operating temps On 27 Feb 2001, at 15:33, Jeramy Ross wrote: > Electron boil-over is only one aspect to mention in this problem. While > older designs are more resistant to that aspect of overheating, older > designs tend to have just as much of a problem to failure due to excessive > heat as newer ones. One needs to look at all aspects of damage due to > overheating. Physically everything starts with electron boiling. The second order effect is that semiconductors tend to have a negative coefficient of resistance i.e. resistance falls with temperature, leading to more current being drawn, leading to thermal runaway. In practise this tends not lead to permanent damage because of the limited current supply capacity and because the negative coefficient of resistance of the semiconductor parts of the circuit are offset by the positive coefficient of resistance of the conductors used to wire the active components together inside the chip. And, yes, however fat you make the components, they will stop working properly once they get hot enough. Eventually the substrate will melt. > > [Hot voltage regs] aren't much to worry about, but that is a fine line that you are > walking here. They either work or cook themselves to death. The fact that > the processor is OC'd may be playing a part here, and there might be more of > a strain on these regulators than the motherboard designer planned for which > may cause a problem in the future, AND if they do fail they tend to take out > quite a few other components on your motherboard with them..INCLUDING your > processor. Their health is a very important aspect. If the M/B designer has done even a halfway decent job, the voltage regulator will present a short circuit to the PSU if it fails catastrophically. So the PSU will shut down & protect the expensive components fitted to the M/B. It's certainly true that overrunning components tends to reduce their life. This should be part of your consideration when you decide to overclock. Having said that, you could (now) replace a whole Cyrix 233 base unit for around $100 - so the risk is not that great. My point is simply that a marginally overheating CPU can lead to processing errors, whereas a marginally overheating voltage regulator won't. > > The processor at issue here is a older design, BUT new enough to merit the > conductive grease or tape. ESP. when the processor is OC'd. If you were building the system NOW, I agree. If it's a question of disturbing a system with a two-year record of reliable operation, you're taking a bigger risk disassembling the system to add the thermal transfer compound than you are by leaving it alone. > > > Don't worry about it. Start worrying > > if and only if you start seeing symptoms which could possibly be > > attributed to overheating. > > Well this is one way of looking at it. Not to get harsh, but most people I > know prefer to keep things in good working order and PREVENT such > problems...not simply wait until they occur. Always better to be safe than > sorry... and when it comes to ones computer...the sorry bit can get to be > quite expensive. Oh, sure. But don't forget there is a risk every time you remove the case cover and start fiddling with the innards. The time to think about "preventative maintainance" is when you're initially assembling the system - which automatically reminds you of the expense, as you'll either just have paid for the components or had them added to your credit card balance. And I _certainly_ agree with the point about case fans - but don't forget that you may need to provide an exit for the hot exhaust air as well as an inlet for cool inlet air. Regards Brian Beesley _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 01 Mar 2001 08:58:14 -0500 From: "Brian Last-Name" <[EMAIL PROTECTED]> Subject: Re: Mersenne: CPU operating temps I took a look at the cyrix web page, and sure enough, 70C is about right for operating temperature. I never thought it should be that high, but that is what it roughly feels like. I have tracked down a good pyrometer that I can use to measure the temperature. I always see these OC'ing websites using gigantic heatsinks and now refridgeration units to overclock, while I was using nothing but stock heatsink/fan. I guess there is something to be said for old tech products! I used to have a PPro in the office with a heatsink and no fan. I took the case off and used it as a coffe mug holder. It did a good job of keeping it hot. (I know, bad idea, but I just couldn't help it.) As far as reliability goes, and the longevity of the processor, I don't really care. If the processor begins to crash and show signs of failing reliability, I will just put in a new processor. These things can be picked up at a PC show for ~$25. Disposable technology at this point of the game. I am not expecting to get another year of use out of the system anyway (before upgrading and using it for dedicated GIMPS processing) As far as ventilation goes, I keep my computer in front of a windows with the case off. It gets a nearly constant breeze going through it, and makes vacumming dust out a cinch. I am just amazed on how hot some processors can run, and other electronics cannot. I work with computers in enclosed spaces, and heat plays a major role in failures with some systems. During the day, I try to debug these systems. At night I beat the heck out of another that just won't fail. I guess there is a lot to be said for good ventilation. _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 1 Mar 2001 11:38:56 -0600 From: "Tom Cage" <[EMAIL PROTECTED]> Subject: Mersenne: Glucas for the Macintosh Glucas by Guillermo Ballester Valor [EMAIL PROTECTED] is now available for the Macintosh. G3 and G4 clients along with complete source code may be downloaded at http://www.belchfirecomputing.com/GIMPS/GIMPS.html Happy Hunting, Tom Cage http://www.belchfirecomputing.com **** Math is cheaper than physics !!! **** _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Sat, 03 Mar 2001 19:11:26 -0500 From: "Joshua Zelinsky" <[EMAIL PROTECTED]> Subject: Mersenne: Lack of pure mathematics coverage. I'm trying to start an e-mail campaign for Sciencedaily.com to pay more attention to pure mathematics. What really irks me is that they had a recent article (12/14/00) about distributed computing that spent half of the article on SETI and didn't mention us at all! They didn't mention Ensor computing either. Maybe the problem isn't that people find SETI more enjoyable but that the media does. Anyways, if you could send e-mails to [EMAIL PROTECTED], I would sincerely appreciate it. Sincerely, Joshua Zelinsky _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ End of Mersenne Digest V1 #822 ******************************
