Question on Thermal sensor reliability on kt7 raid.

[Balael]

I've had my duron 600 oc'ed to 1000 for about a week now, and it started off to be idle at about 39c then 38c, but now it's down to 34c at idle. Is this just the heatsink getting broken in? or is the thermal sensor on the motherboard not that accurate? it's right about my room temperature, it says it's 23c. Anyone else getting these temps with a duron 600 and a fop32? or any other kind of hsf? thanks.

balael

 

[Mikewarrior2]

What kind of voltage is your cpu running at? Depending on that, you'd be producing anywhere from 50 to 60Watts of heat.

With your global fop32, your best hope for cpu core temp would be 43C(and if you're within 2-5C of this for actual core temp, you're doing great). The problem with the thermistor temp measurement is huge.

some problems include the fact that the thermistor readings are more dependant on ambient case temp than cpu core temp readings(since the thermistor not only contacts substrate, but also air). So the temp drops you're getting are likely due to thefact that air temp has been dropping off lately.

What bios revision are you running? Later KT7 bios' auto-compensate the cpu temp readings to help compensate for inaccuracies. They still aren't accurate with this method of correction, but at least the peak temp reported by the mb is near what hte peak cpu core temp should be(i'd say anywhere from 2-5C off). It still won't show full cpu temp movement range from idle to full load, though.


Mike

 

[Technonut]

Hmmm, I have an external thermal probe placed so the tip touches the side of the core, and at 1.85V it right now shows a temp of 33.7 Cel, while the VIA monitor shows 31 Cel. The internal case temp is showing as 20.5 with another probe, while the VIA monitor shows the system temp at 18.

I double checked that my probe is touching the core, and have it in place on the CPU with frag tape. When under load it rises no higher than 37-40 depending upon room temp, and falls back when idle. I checked the probes against the house mercury thermometer that I have, and they are accurate with that one within 2 degrees.

 

[Balael]

My cpu is running at 1.7v, or sometimes 1.675, i change it pretty often, but mostly now it is at 1.7. Right now i am idling at 35, with again the reading of the room temp at 22. When i just turned my computer on it was up to 37, but i guess that was only because it was under load. I am having no stability issues, but i guess i just wanna double check to see whether or not these readings are accurate. I think i'm running the latest bios, but not sure, how would i check that? thanks for the help.

balael

Duron 600 oc'ed to 1000 at 1.7
Kt7 raid with fop32

 

[Mikewarrior2]

Technonut,

The KT7 uses a thermistor underneath the socket that touches the backside of the cpu. Unfortunately, the back side of flip-chip manufactured cpu's are much cooler than old socket cpu's, so the temp measurement here is about 10-15C lower than what actual core temp would be.

oops, just realized that you're using an external probe. however, at your voltage/heatsink, you should be getting a cpu core temp around 40C at best. You could have your thermistor positioned up against the l2 cache of the cpu(which runs much cooler than actual cpu core).

Update: Senfu versus Cpu Diode ReadingsDiode vs Thermistor. The Senfu Uses a thermistor to measure cpu temp(the thermistor is supposed to be placed up against the cpu core side). As you can tell, it is still fairly inaccurate, as it not only measures cpu core side temp, but also air temp around it.

Balael,

It would say something like UL at the end of the bios during the startup screen.


Mike

 

[Technonut]

So, are you saying that it is impossible to get an accurate temp reading with the T-Bird's? My probe is placed exactly like the one in in link that you provided. Senfu ReviewThe only difference is that they have it on a P3, while mine is on an 800 T-Bird.

It is not possible to place the sensor directly on top of the core since it would be crushed by the HSF. I guess that I have it setup as accurate as I can get, and have no choice but to be satisfied with it.

 

[Mikewarrior2]

That's exactly what i'm saying. There is no way to get true CPU core temp on any SOcket A cpu with conventional "cost-effective" methods.

You've got the closest to accurate that you can get, but most people on the BBS are relying on hte under socket thermistor in socket A mb's(which is even more inaccurate than your method).

And sometimes the thermistor is placed incorrectly with people attaching one like you are. Look at the insanehardware super orb review today. The thermistor probe isn't even touching the cpu core. so the temps htey are getting are much, much lowre than what core temp would be.

This isn't a knock on you, cause you're doing the best you can with a crummy situation. Unfortunately, a lot of other bbs user's rely on the under socket thermistor as rock solid readings of cpu core temp.


Mike