The problem is with speedfan. I have the same issue. When I use the software that came with my motherboard, everything is fine, but once I start speedfan it shows completely different temperatures way above the normal limit.
I just had a BSOD while playing Crysis a minute ago. Here's a detailed version of what happened.
My CPU temp hits 111C all of a sudden just after closing firefox. I restart the computer thinking that the temps will be reset to normal. I get into Vista and my CPU temp is at 45C idle (normally is about 24C). I'm wondering whats going on so I load up Crysis to stress it a bit and see if anything happens. ~5min into the game BSOD. Pretty sure it said something about shutting down due to high temps, but it went by pretty fast.
make sure you are not confusing core temperatures bro. it honestly sounds like your temps are through the roof, like i said it in my previous post, your comp should have shut down which is exactly what happened. try this:
1)stress the computer and take your hand and put it on an exhaust fan does it feel warm/hot air blowing out? if so, temps are probably correct
2) re apply the heatsink, expecially if its a stock INTEL heatsink. those things suck and they never stay on, you have to snap your mobo in half just putting them in
3) make sure your CPU is not heavily overclocked or not receiving higher voltages than it should be.
edit: if i had to take a stab at it im 90% sure one of your snap in pins for your heat sink is not seated properly with the mobo.
Crysis can get picky with drivers causing issues, so I wouldn't blame temps right away. Can you post a picture of SpeedFan when the temp "spikes"? Your BIOS version affects "CPU temp" readings too, and there could be a bug in it. Run Real Temp as Shadow mentioned and check to see if the Thermal Status is LOG (throttling has occured while Real Temp was running) or HOT (throttling is happening right now) when the CPU temp is 111C. If it isn't, then as I expected this is simply a bug.
It hasn't happened again since the original post, but I'll check and make sure the heatsink is seated properly. I was thinking the same thing when I had the BSOD, but some of the other things don't make sense. Like the fact that the CPU temp will be at 111C but the cores are at like 40-50C.
It is the motherboard''s problem, it reads the temperature wrong and restarts. This happened to me before, got fixed by replacing the motherboard. Try to reset the HSF first. Did you put enough thermal grease?
I noticed an odd thing on the ASUS site. I went to look at the BIOS downloads available for my motherboard. The only one it shows to download is 1406, but if you click the bios history link next to it, it shows the most recent as 1611, which is what I'm using currently. I must have downloaded it from ASUS update.
Surely you can test that temp by just touching the chip. If your hand burns then speedfan is correct. Ofc this will be a lose lose situation because you will have burnt fingers AND need to pump cash into your rig.