Weird CPU temp spikes with FM2A85X

[Donny Bahama]

My PC has shut down 3 or 4 times in the last week. Each time, the screen just suddenly goes black and when I restart and check the CPU temp, BIOS reports it as very high.

I ran Memtest overnight and came up with 1600 errors on 5 passes, so clearly the RAM is bad - but is that cause or effect?

This is a fairly new build (< 1 month) with an FM2A85X Extreme6, A10-5800K cooled by a Zalman CNPS9500A, G.Skill Sniper DDR3-2133 RAM, and an Antec Neo Eco 520 power supply. After building it, I ran Prime95 for over 24 hours. The system never broke a sweat.

I'm confident that it's not a cooling issue. The Zalman cooler is highly rated, and I've got multiple case fans and good airflow. I monitored temps while running Prime95 and everything stayed nice & cool no matter how hard I pushed. Additionally, I now (since the first temp spike) have the CPU fan maxed out and it's the loudest thing in the system. I'm sitting 2 feet away; I'd definitely hear it if it stopped or slowed.

Nice & cool is the status quo since the initial build (except for these weird episodes). Since this started happening, I've tried to keep my eye on Speedfan in the tray. At the moment, CPU is 85F, System is 82F and HDDs are at 79F and 75F. (GPU reports 27F but obviously that's not accurate.) The machine stays that way for hours - even days - under varying loads. (Even with tons of tabs open in Firefox while simultaneously working on some really huge images in Paint.net.) All the while, I'm seeing CPU temps in the high 80s/low 90s. Then, next thing I know, my monitors go black and the system goes into (what I assume is) some sort of protection mode. I immediately restart and check HW Monitor in BIOS and the CPU temp is scary high.

Setting cooling aside, what can cause these sudden CPU temp spikes? I know for sure the RAM is bad (unless Memtest has it wrong) - and the machine never got hot during the memory testing. (AFAIK - it ran overnight and was cool (low 80s) when I checked it the next morning.) Replacement RAM is on its way but I can't imagine how bad RAM could cause an extreme temperature spike - and I'm worried about toasting two more DIMMs.

I can see how this could be a CPU problem, I can also see how it could be a motherboard problem or a power supply problem. How the heck do you troubleshoot something like this if you don't have a spare mobo, CPU & PSU?!

[parsec]

Why would a high CPU temp cause the DIMMs to be damaged? Even if the warm air from the CPU cooler was directed at the DIMMs, that air is not that warm. You seem to be implying that your current RAM was damaged by heat?

I would try something else besides Speedfan, and since it can auto-start, be sure it is not running or uninstalled. Multiple monitoring programs running at the same time can cause incorrect readings. Have you tried ASR's AXTU, it's not bad at all. I like HWiNFO64.

You could also make random trips into the BIOS and check HW Monitor, not only when the PC black screens.

[- wardog -]

I've "toasted' DIMMs before. As attributable it was caused by the loosening of the MB mounting screws and I'll assume the screws(yes, plural :( ) were shorting/arcing over time.

2nd vote for HWiNFO. Watch your voltages too.

[larhome]

I took a look at a review for your cpu cooler and it may be a warped base plate causing hot spots.
I would remove it and check for flatness and hone it down if needed.