I don't think I made the "Thermal Monitor" feature clear enough. From what I've read at Intel's website, I believe it is built onto the P4 chip, independent of the motherboard except that the motherboard has to activate it at boot. In any case, the BIOS menu that I have access to on a Intel D850GBC is not exactly verbose...it has nothing letting me change timing settings on any piece of hardware, and nothing about CPU throttling.
And I definitely do not want to deactivate Thermal Monitor and simply ignore cooling problems...that would likely cause damage to my CPU. For cooling, in addition to the power supply, I have a case fan in the bottom front that is pulling air in, a fan on the CPU heatsink (the one provided by Intel), and a case fan next to the cpu pushing air out. There is also a weak 5.25" HD fan pulling air in from the front. Regards, David Meyer ([EMAIL PROTECTED]) [EMAIL PROTECTED] wrote: > On 22 Dec 2001, at 18:55, Paradox wrote: > > >>As I email'd previously, I have an Intel Pentium 4 1.9 GHz with PC800 >>RAM in an Intel D850GBC motherboard running Windows 2000. Even with no >>other programs running, and a minimal of services, (100% of cpu >>dedicated to prime95), I get approximately 0.180 seconds/iteration. >>According to the benchmark on mersenne.org, I should be getting closer >>to 0.143 seconds/iteration. >> > > Interesting, that's almost exactly 80%. > > >>I suspect that my Pentium 4 may be engaging >>its built in "Thermal Monitor" feature, which is mentioned on Intel's >>website, without extensive documentation (as far as I can find). The >>Thermal Monitor is a temperature sensor inside the Pentium 4 which >>detects when the processor is getting too hot and reduces system >>performance in order to compensate. >> > > Most BIOSes have a setup which allows you to change the throttle > ratio (the realtive clock speed when throttled) and the threshold > temperature at which throttling is applied. If you find a throttle ratio > of 80% then you've got it. If you find the throttle ratio is set to 50% > then the throttling theory is wrong, you'll have to find the cause > elsewhere - try using the Task Manager to see what else is running. > > >>I have noticed >>using my motherboard's temperature sensor (different from the internal >>P4 sensor), that Prime95 raises my CPU temperature from approximately >>90 to 95 F to exactly 124 F, which is immediately below an indicated >>threshold. This makes me suspect that the P4's Thermal Monitor >>is engaged and could be causing the performance decrease. I have looked >>for, but have not found, a way to detect whether or not the Thermal >>Monitor is infact being activated. I want to make sure this is the case >>before taking drastic actions on my CPU's cooling system. Any help would >>be appreciated. >> > > 124F = 51C ... sounds too hot for the system board sensor ... 51C > may be OK for the CPU sensor, though. Mind you I'd expect the > threshold to be at 50C or 55C rather than 52C. > > If your system board sensor really is reading 124F then you almost > certainly have a problem with case ventilation. Is the case fan(s) (if > fitted) running? Is the fan in the PSU running? You don't have a > strange problem like the one I found last week, where the PSU fan > was reversed, thereby blowing pre-heated air into the vicinity of the > CPU cooler inlet? > > If you can't spot a problem like that, try adding another case fan. > Most good cases have fittings for relatively cheap (think $5) 8cm > cooling fans. Normally you fit these so that they blow into the > case; it is usually obvious if this is wrong i.e. the fan is mounted so > that it is adjacent to the CPU in such a position that, if it were to > suck rather than blow, it would be getting a high proportion of its air > from the CPU cooler "exhaust". > > If your case doesn't have fittings for an extra case fan, you can get > a "HD cooler" (two or three 40mm fans in a plate which will fit a > 5.25" drive bay). Try one of those. You can also get extractors > which fit an expansion slot; these are useful for cooling e.g. > graphics cards, but also help keep the rest of the case volume a bit > cooler. > > Disabling thermal throttling by setting the throttle ratio to 100% or > moving the threshold temp way up is also acceptable _provided the > system passes the torture test_ after changing the parameters. In > fact this _might_ be the best way to fix the problem, since your > m/b may have a minor problem (possibly duff BIOS software - did > you check for an upgrade?) causing throttling irrespective of > sensed temperature. > > You might also want to try the torture test with the system clock > temporarily wound up a couple of percent and/or a case fan > disconnected; if the system is stable & error-free under those > conditions, it should be OK in normal service. If you try this please > watch the system carefully & return to normal if it shows signs of > instability or logs more than a very occasional error in the torture > test. Mild overheating will not cause permanent damage but > prolonged, severe overheating might. > > Seasonal felicitations > Brian Beesley > > _________________________________________________________________________ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
