AMD FX8120 8 Core Processor and Heat

#1 65C is definatly not something I would consider overheat, Frank. Maybe a few years ago, but not now. My laptop idles at around 40C, peaks at 70C.

My gaming rig idles at 40C too, while it can peak to 90C.

What does your case look like? Have you setup proper airflow with intake fans blowing towards the hotspots, removing air backwards out?

I've had a Phenom Quad overheat at 100C because of bad case layout.

#2 Ummm, I don't think so:
www.overclock.net/t/1134229/amd-cpus-max-temps

My computer monitors complain when my 8120 gets to 65 deg C. According to that link 61 is the max it should get to. I am talking CPU core temperature.

Edit:
This might be a better link:
www.legitreviews.com/article/1741/18/

#3 I just changed out the thermal paste from the stock heatsink to some Arctic Silver Ceramique 2. At idle it seemed to drop fromk 42 deg C to 39 deg C. When running a somewhat CPU intensive program it looks like it is maxing at 50 deg C so far. It was running 55 deg C with the same load. It looks like the problem is not the stock cooler, but the stock heat transfer compound.

I read somewhere that you should NOT use DEFAULT bios settings on these CPUs. That seems kind of silly, but hey if it keeps the temp down then that is good. One article said to drop the voltage on the CPU as low as is stable. The context was overclocking, but the idea was to give the CPU more head room. Apparently if you can run at 1.2 V then the CPU is of higher quality than most supposedly.

The next thing I am going to try is turning on the max saving energy settings. I kept the settings at the middle range settings before. I read as well that maybe I should be turning Turbo off. Again the context there was overclocking and keeping voltages in check to prevent overheating. I don't intend to overclock, but using their knowledge to make it run more efficiently is a good thing.

Wow, this is still running at a solid 50 deg C where before I changed voltage settings it was running at 55 to 60 almost. All I changed was the thermal compound.

#4 If you want to stress test your computer and heat dissipation setup here is the program to do it with:
www.mersenne.org/freesoft/

This thing after like 4 or 5 minutes pushed my current setup with better thermal paste and stock cool up past 65 deg C. It pegged all 8 processors to the max. I mean, solid max CPU usage on all 8. I used the 64 bit version because I am running 64 bit OS and system.

I think after running this program I will invest in a better cooler down the road. I don't like the idea of a program being able to max out the CPU and possibly damage something. Hopefully this will help people here doing development. It also tells me that a game that maxs out all the CPUs on a customers machine might actually make some customers really mad especially if it damages the machine.

#5

Quote:My computer monitors complain when my 8120 gets to 65 deg C. According to that link 61 is the max it should get to. I am talking CPU core temperature.

Well, that's not the maximum temperature limit or anything like that. It's just a reference temperature limit that someone came up with that you should try to stay below.

If you look in your CPU manual there's a "Junction Temperature Max" specification which specifies the maximum temperature of each individual core. You should try to stay 20% or so below that to be "perfectly" safe (though you're never safe), which might explain the numbers in your link.

For instance:

AMD Phenom II X4 955 BE (Deneb): 90C
Mobile Intel Core i7 2720QM (Sandy Bridge): 100C

You should obviously keep it as cool as possible, but I wouldn't worry about 60C core temps when you stress your rig. :)

#6 @Stefan,
I was more worried about the red lettering AI Suite II has on the sensor data and the popup warnings it was giving me. I am assuming the MB manufacturer has a good idea of what is too high.

The only official documentation I can find from AMD is this:
products.amd.com/pages/DesktopCPUDetail.aspx?id=771&f1=&f2=&f3=&...

I even found their BIOS developer guide and nothing about temperatures. Where are you getting your information on the AMD max temperatures. AMDs website is horrible for finding documentation on their processors. I am an electrical engineer and one of the first things I look for are temperature ranges of ICs. Not having this information readily available is nuts.

#7 Okay, I have been mixing apples and oranges. I thought I was reading core temp. I have been looking the MB cpu temp. There is almost a 10 deg C diff between core and MB temp. That shows me that I am below 61 deg C when the alarm goes off.

At fully loaded it actually stays stable at 55 deg C on all core temps for a while, then it started creeping up again. I am thinking I may need a better cooler down the road, but unless I really peg it then it stays below the AMD max for this processor.

#8

Quote:
Where are you getting your information on the AMD max temperatures.

They're not max temperatures, they're TjMax values. I guess it means that at the heat level specified by TjMax you risk meltdown of the CPU material.

Quote:
I am assuming the MB manufacturer has a good idea of what is too high.

Me too. But those motherboards can also house different CPU's (even with the same socket type) which have different Max Junction Temperatures. Maybe they account for that, I don't know..

This is what Intel has to say about Max Junction Temperatures:

Quote:
"Tjunction Max is the maximum temperature the cores can reach before thermal throttling is activated. Thermal throttling happens when the processor exceeds the maximum temperature. The processor shuts itself off in order to prevent permanent damage."

Which makes sense. I have no good source for TjMax values other than the ones you can fetch from the hardware directly. Core Temp (the application) does this, for instance.

But I've also heard TjMax is less relevant for desktop processors as these have heat spreaders, unlike most laptops. Intel states that in this case they specify a "Max Case Heat Temperature" or something similiar, but I have no idea what it is or if AMD does the same.

You can probably tell I'm not an electrical engineer (;P), I just happen to have built a few dozen workstations and servers. I would trust AMD with their 61C max temp specification.

#9 Yeah, I don't know how Intel does their stuff. The last time I spent much time messing with Intel CPUs at this level was years ago trying to overclock 486DX 66 processors with a 40Mhz bus instead of a 33Mhz bus. Since then I have not done much except use the things.

I am much happier now that I addressed the heat issue and I now see the limitations of the stock cooler. Putting on better heat transfer compound and adjusting the voltages has made a huge difference in heat production and dissipation. I may add a PWM controlled fan or two to the case and tie at least one of them to the secondary CPU fan control. This will add case air flow as the CPU usage ramps up. Down the road I will try and pick up a nice looking copper heatsink. Mostly because the all copper ones would look really nice on my motherboard. But seriously, how often do you really look through those stupid case windows?

@Stephan,
Thanks for helping me figure this out. You gave me some good ideas by looking to see if I can see some of the specs on the AMD chip. I am using AMD OverDrive and just found I can see a lot of the internal specs of the processor that way. I cannot see any temperature info as far as max though. I did see that the max freq on this chip (as far as the multiplier can go) is 6300Mhz. I know I would probably need nitrogen for that though. :)

#10 I decided to get a little crazy. I dropped the core voltage from 1.2125 or so to 1.1. I am running Prime95 to compare and so far 10 deg C cooler at full 8 core load. Running at a very stable 44 deg C. I am flabberghasted at this. Shaving 0.1125 volts off is still stable so far and 10 deg cooler. That is amazing! This is kind of neat that you can even tweak this stuff.

#11 Just an update.
Running at 0.1125 volts lower than the default by using offset settings in the bios has GREATLY dropped my heat production on my CPU. If your chip will let you (is stable) then I would suggest doing the same for the FX8120 from AMD.