Core temps versus CPU temps

[purplepanda]

Hey all, I'm new here, but I figured someone here might have the answer I'm looking for. A few months ago I built my first PC. I bought an Athlon II X3 455 because I heard it was good for unlocking a fourth core, and I also bought an Asus M4A88T-M motherboard. After putting everything together and installing Windows 7 and whatnot, I tried to unlock the fourth core, and it worked without a hitch.

The PC was made for gaming, and I wanted to see if I could overclock it, so I downloaded Coretemp and HWMonitor. The idle core temps without the extra core were pretty low (around 28C), and with the fourth one weren't much higher (32C). Whenever I gamed, they went up to a max of around 50C, maybe a few degrees higher. But I noticed, the CPU reading is always a fair bit higher (40C with three cores). When I start playing games it gets a little past 55C, which I've seen in some places is the max for this particular CPU (I haven't been able to find any info about that from AMD).

I tried a Prime95 stress test, and with four cores the core temps went up to around 50C and the CPU 60C in just a few minutes. The results were a little better with three cores, but in both cases I stopped before the CPU temp got higher than 60C. All of this is without any overclocking.

What I really want to know is, which should I be looking at, the core or CPU temps? There's almost always a ten degree difference there. And also, what's the max temp I should be running this CPU at? I've seen people recommend anywhere from 55C to 72C. I haven't had any issues so far with blue screens or shutdowns, but I'm a little freaked out it's just going to explode and then I'm going to have to start all over.

Specs:
AMD Athlon II X3 455 w/stock fan | Asus M4A88T-M motherboard | Seagate Barracuda Green 1.5 TB HDD | Corsair 8GB DDR3 1333 RAM | EVGA GTX 460 | This case with a Rosewill Green Series 630W Power Supply | I added a 120mm outtake fan in the back (Should I take this out or change the direction? I have one 80mm intake on the side and one 80mm outtake on the top. Thinking about adding two 80mm input fans in the front (in front of the hard drive area), but is there any point with this case? Wouldn't the front panel block all of the airflow?)

Thank you in advance for any help. ~

 

[trents]

You should be looking at both and you don't want either to exceed 70c, and I would say 65c as a hedge for safety sake. Your are on the brink of that. With stock cooling the core temps typically are a few degrees higher than CPU socket temps. With good aftermarket cooling the socket temps are typically higher than core temps, often about 10c with that family of CPUs. There has been a lot of discussion on the forum lately about this very matter. One of the problems is how core temps are calculated (they aren't really a direct temp measure) and the variability (accuracy) with regard to core temp sensor calibration.

 

[RGone]

AMD Athlon II X3 455 w/stock fan = When he 'unlocks' that Cpu he wlll not get Core Temps in HWMonitor anyway. Unlocking kills/disablles the CPU CORE TEMP circuit.

 

[purplepanda]

So the core temps aren't reliable in this case, and the max the socket temps should be is 65C? Okay. Could either of you recommend a good fan for the AM3 socket? My budget would be around $20-40.

Thank you.

 

[R3divulpis]

AMD Athlon II X3 455 w/stock fan = When he 'unlocks' that Cpu he wlll not get Core Temps in HWMonitor anyway. Unlocking kills/disablles the CPU CORE TEMP circuit.

I was wondering about this myself...

I have the same board, running a Phen2 x3 720BE @ 3GHz. I usually get around 18*C on idle, and not more than 38*C on load.

Every time I've enabled the 4th core my temp readings are thrown out of wack because of the disabled sensor. This is the main reason I haven't kept #4 unlocked, because I'm paranoid (I realize unduly so).

I did try to run an external temperature monitor, but couldn't get the probe to work right. My own fail really.

OP, how did you monitor temps with the 4th core unlocked?

 

[purplepanda]

OP, how did you monitor temps with the 4th core unlocked?

The fourth core showed up alongside the other three in HWMonitor and Coretemp. It was the same temp as the other three +/- 1C. I can post a screenshot if you like.

 

[R3divulpis]

The fourth core showed up alongside the other three in HWMonitor and Coretemp. It was the same temp as the other three +/- 1C. I can post a screenshot if you like.

definitely... I'm wondering if it might be due to our processors being different series, but it wouldn't make much sense... Then again, this is my first Phenom, as well as the first setup I've really paid much attention to as far as cpu temps go.

Also, thanks for the info trents, I've been wondering that myself. I usually pay more attention to the cores themselves, but I'll watch overall temp as well a little closer now.

 

[trents]

Two things:
1. Before you unlock your CPU you should run a 20 minute Prime95 blend run and note the differential between CPU socket temp and core temp. This differential will remain constant whether you run it as dual core or a quad core or whether you run it at stock or overclocked. That way you can calculate the core temp but doing the math. As RGone pointed out, when you unlock cores you lose the ability to monitor core temps directly because the unlocking process interferes with the reading or the reporting of the core temp sensor. So if you have already unlocked the cores, I strongly suggest reversing that temporarily until you can establish the delta between the two temps.
2. There is only one core temp sensor total on the CPU die since the Athlon 64 X2 days. That's why all the core temps readings are so close together. The software is reading the one sensor x number of times (x=the number of cores) and reporting it at regular time intervals as though there were a sensor for each core. It's the time interval that is responsible for that 1 c difference.