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NF7-S v2.0 Temps... Which Reading Do I Go By?

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plexdude

New Member
Joined
May 4, 2003
Hey all,

This post is for all of you that own one of the NF7 series Abit boards.

As many of you may already know, the most recent BIOS releases (1.9 for NF7 rev1~1.2 and 1.4 for NF7 rev2.0) have been adjusted in such a way that CPU temperatures are now more "correct". The difference in these temps register about 7 to 10 degrees C lower than earlier BIOSes. However, some may argue that the previous BIOSes reflected a more "true" temp reading as these older BIOSes tried mocking what the actual die temperature is. Now I've read several posts in these forums that most people suggest that when OCing your 1700+ T-Bred B DLT3C to make sure the temp does not exceed 50 degrees C to ensure longivity of the CPU's life. So my question is, when you guys are saying 50 degrees C, which BIOSes would more correctly reflect this suggested temperature limit, the older ones or the very newest releases?
 

Stiletto

Member
Joined
Mar 15, 2003
Location
GA
From what I've been reading, the lower ones are closer to correct.

But again, thats what I read.
 

jonspd

Super Speedy Senior
Joined
Jan 18, 2003
I think if you where to go by the following you will figure out which is the correct temp MBM5, cpucool, bios, and whatever program came with you mobo.
 

Gautam

Senior Benchmark Addict
Joined
Feb 4, 2003
Location
SF Bay Area
All software simply uses the data gathered from the motherboard's sensor, so it doesn't matter which one you use.The update in beta bios v1.4 "corrected" motherboard temperature readings according to Abit. I'm very skeptical about the temps that this "fix" gives me. They seem plain illogically low. The older BIOS' temps prior to v1.4 seem far too high though. The problem with motherboard readings, especially in-socket thermistors, like the NF7 series have, is their incredible variability and inaccuracy. For example, they often report better temps for aircooling rather than watercooling simply because airflow makes the thermistor cooler, when in fact the core is actually a lot cooler with water cooling. What this means for you is that you shouldn't take temperature readings too seriously. I didn't trust my old readings, and I don't trust these new one's either. I can't say with any certainty which one reflects real temps better, and no one really can. Use stability as your gauge instead. Your cooling is very good, so temps should not be an issue for you at all until you cross around 2.5ghz or so. 50° C is a nice round number and used by many as a point to stop overclocking further. I have found that these processors can actually run with a great deal of stability far past 50. There are several on these forums that have very similar setups to yours, and are running them past the 2.5ghz mark, ensuring temps well above 50, yet still do not compromise stability or life too much. Again, its going to be very unlikely for you to even be able to reach a dangerous temperature range with your setup, so rely on stress programs such a Prime95 for stability. If it passes, there shouldn't be anything to worry about.
 

hitechjb1

Senior Member
Joined
Feb 2, 2003
I have an A7N8X-DLX and have similar question about the accuracy of the CPU temperature reported. This is a post discussed about how stability and sensitivity of temperature to Vcore can be used instead of a fixed, predetermined value of max temperature.

Link: Temperature measurement and importance of HSF
(Tbred B 1700+ DLT3C 2.5+ az air results, page 4)


hitechjb1 said:
Temperature measurement and importance of HSF

Yes, I have not attempted to measure or calibrate the temperature probing at this point in time. Also I have kept the same ASUS probe program version the same during the oc history of the 1700+ and have not changed the CPU temp sensor.

One thing is indeed the SLK-800U plus a Ventac Tornado fan lower the temperature cooled by a SK-7 and a TT SFII, by about 8-10 C during max overclocking.

The original analysis is that for same 5500 rpm, the SLK-800U would be better than the SK7 by about 3C given by the CPU thermal power x difference in thermal resistance of the two HS.

thermal_power = 50 x 1.95 x 1.95 x 2.6 / (1.5 x 1.5 x 1.467) = 150 W
del_temp = thermal_power x del_thermal_resistance = 150 x 0.02 = 3 C

But it looks like the Vantac Tornado at 5700 rpm (84.1 CFM spec) delivers the 5 to 7 C advantage during maximum overclocking compared to a TT SFII at 4800 rpm max (75.7 CFM spec).

As I said in the past, the absolute temp measured is not as important as getting a "feeling and monitoring" of how the temperature is changing during Vcore increase at each step of the overclocking at max load. Since temperature increase will indicate/track how the internal Icore current (cannot be measured directly at this time), leaking current, and power pumped into the CPU for heavy computation.

If temperature increases (delta_temp/delta_Vcore) at a much faster pace than Vcore, the system would become unstable and crash during boot or even during idle time. It indicates that overclocking has reached a wall or limit for the given setup of HSF and PSU. I hit such wall a few times during these experiments, if you read the history of this thread, from PSU limitation, to fan limit, to HS limit, etc, etc.

I use the sensitivities of temperature to Vcore (delta_temp/delta_Vcore) and clock frequency to Vcore (delta_frequency/delta_Vccore) as the indicator rather than just the absolute temperature. It would be even better this way than just based on a perceived, fixed limit on CPU temp. The temperature reading can be off by 10-20 C, and there is no way to tell when to stop if just based on temp reading alone. The system would become unstable way before reaching the 85-90 max die temp limit.

I find that for this type high curent, high power CPU, the die temperature has to be kept under 40 C in order for effective overclocking, i.e. delta_frequency/delta_Vcore >= 1, and max temp has to be under 50 C for stability.

The system ambient temperature is around 25-28 C measured, whatever it is reported by the ASUS probe program, during all these runs. The room temperature has been around 21-23 C (70-75 F) during most runs. At least the room temperature and system ambient temperature are consistent within 4-5 C, system ambient temperature being higher, of course.
 
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