TPFC vs HWMonitor- which to believe?

Okay, this is a pretty quick question but it has me scratching my head.

I've got my T500 sitting next to me doing a pretty lengthy(2+ hour) video converting project. I've got TPFC running as well as HWMonitor to monitor my temps, as I've just repasted the GPU and CPU with Arctic Silver 5. I've got TPFC reporting the CPU as running at 56-58C, but HWMonitor is reporting between 48-50C, running full-tilt(95-100% CPU usage on a constant basis). So, which program is providing the more accurate reading?

 

I don't know which is most accurate, but both values are very very safe temps.

 

THey definitely are. I'm just scratching my head as I've never seen an improvement in load temps this dramatic from a repasting before, and I've done several AS5 jobs on previous notebooks. It's really encouraging; I'm just curious as to which one's more accurate.

 

The thing is, Intel CPUs do not know how hot they actually are; they know how far they are away from overheating and throttling (and maybe shutting off). I believe HWInfo uses a TJMax of 100C, so that would mean that your CPU is 50C away from throttling. That is really low, though. I'd expect at least 65 ~ 70C (i.e. 30 ~ 35C away from TJMax) when a laptop CPU is under full load.

 

Compared to other monitors, HWMonitor is, for me, usually about 5 degrees too low. On the other hand, TPFanControl is usually on the high side. It all has to do with the offsets used in the programs, though. I've found CoreTemp to be a very accurate program for Core 2 Duo laptops.

 

Tried HWiNFO32 or HWiNFO64 for comparison?

 

HWMonitor reports two sets of values for me. One which corresponds to TPFC's value, and the other corresponds to RMClock's value.

They're supposedly just sensors on two different locations.

 

To get reasonably accurate full load core temperatures, software has to use the correct TJMax value for the CPU. Intel has set most of the newer 45nm Core 2 CPUs to 105C but HWMonitor uses 100C which is wrong so it reports core tempreatures on these CPUs 5C too low.

Head to the Intel website and you can look up what the correct TJMax value is for your CPU.

ARK | Your source for information on Intel® products

The correct value for a P8400 is 105.

http://ark.intel.com/products/35569/Intel-Core2-Duo-Processor-P8400-(3M-Cache-2_26-GHz-1066-MHz-FSB)

Exit HWMonitor and edit the hwmonitorw.INI file and change this line.

CPU_0_TJMAX=105.0

Once you have corrected that, HWMonitor should be fine. The newer Core i CPUs don't have this problem since Intel finally started writing the correct TJMax value to each core of each Core i CPU.

 

That works extremely well. Thanks! Also, as an aside, HWMonitor should be displaying temps more accurately out of the box with any 'Core i' processor, meaning that my G73(with an i7 740QM) should be getting accurate readings off the bat?