[SOLVED}] Core 2 Quad only 2 core overheat

[robb7979]

Hello Tomshardware!

I need your genius. I have a new build, specs below. My first MB was DOA, so this is my second. I am seeing CPU throttling. I've used a few core temp monitors, and they all show me as having over 100C on cores 2 and 3 (cores 3 and 4). They show those cores as reporting PROCHOT, and I am definitely seeing this. With thermal prot disabled, the CPU will ramp up it's multiplier, but still seeing throttling with a benchmark test. I have tried to reseat the HSF (stock) several times, using the horizontal line method recommended for thermal paste. I've tried every available BIOS. I tried switching to Win7 32 bit, and the temp monitors showed cores 1 and 2 (cores 2 and 3) overheating!! Different core mapping? BIOS always shows CPU temp as 37-38 at idle. Core temp also shows normal CPU temp

What can be causing this? Can only 2 cores of a quad overheat? Is it the CPU? BIOS? MB? Help!!!!!

GA-EP45-UD3L
Q9650
8GB Patriot DDR2 800
GTS 250
WD SATA 1TB x2
Win7 x86 or x64
Mac OSX 10.6.2 (hehe)
Antec 300 case 2 fans

 

[Klosteral]

Ok. This is a new issue that I have not seen before but there are only so many things that could be going wrong.

My first thought is the way your CPU is sitting in the motherboard. Check to make sure the whole CPU is sitting in there properly and check the heat sync is fully attached.

Then check the CPU cores in the BIOS. Have a look-see to make sure all the cores are outputting the same amount and/or using the same amount of power.

Do you run Windows and Mac at the same time? If you do, there have been rare cases when one OS is more demanding than the other and so overclocks half the cores while leaving the other half as normal.

On a different note, I am running a x86 version of Win 7 and was wondering if I should "upgrade" to a x64.

Good luck

 

[robb7979]

Klosteral,

Thanks for the reply. I have reseated the CPU and checked the pins/contacts several times, but will try again.

I didn't see any options for checking individual cores on any version of the BIOS. I can only see temp, voltage etc for the CPU as a whole.

Windows and Mac separate times, separate HDD. I even unplugged the MAC drive and did a fresh install.

Heatsink was/is fully attached. I guess this may be what I will try to replace first. Maybe the bottom isn't flat. I have another brand new Intel stock cooler, and I'll pick up an after market cooler this weekend. I just didn't think only 2 cores could overheat, being so close to the other 2.

I have another backup CPU, but it isn't multicore, so I don't know if that would help me rule out the CPU.

I wish I could give you advice on whether or not to upgrade to x64, but I haven't been on either long enough. I just took the plunge from XP when I built this machine!

-Rob

 

[azconnie]

I have a quad, core zero reads -7, and core 3 reads +7 compared to core 1&2. If your really getting 100*C, 1 you could feel the heat, and 2 the CPU should shut down (shut down temp is 75 I think). Try a different temp monitering program just to see.

 

[robb7979]

That's exactly what I thought. The back of the MB is warm, not hot. From what I've read, and some information is conflicting, throttling will occur at 75. Either through bios or through internal prochot on the CPU. Shutdown happens when the die temp reaches thermtrip? I'm wondering if there's a problem with the digital temp sensors on those 2 cores. I've used core temp, real temp, and fan speed. Same same. Maybe I'll pick up a 9550 on sale for 179 and check that.

 

[robb7979]

Solved. It was the CPU. From what I've read the Core 2 Quad is basically 2 core 2 Duos stuck together. One of those must have had some problems somewhere, which is why half of it reported over temps. Had to downgrade to a 9550. Maybe I can get an RMA on the 9650. Idle temps now 37-39 across all 4 cores.