E6300 wild temperature variations

[auldar]

Hi guys,

I'm looking for some help.

I've been trying to work out the cause of very wild temperature fluctuations between idle and load, and between Tcore and Tjunction.

I've read and believe I understand CompuTronix's guide.


My system:

Asus P5B Deluxe WIFI (BIOS 1004)
E6300 C2D
Corsair PC-6400 (5-5-5-13@DDR800)
Thermaltake Big Typhoon
AS5
Silverstone LC20M Case
2 X 92mm Front intake fans
1 X 80mm side intake fan (blowing on CPU cooler)
2 X 80mm rear exhaust fan

I'm not happy with the front to rear air flow, however given the fan blowing on the CPU cooler from the side intake, and the 2 rear exhaust fans, I believe the CPU cooler is getting enough airflow. Perhaps your interpretation of my temps will cause you to disagree - I'm very open to suggestions, although at this stage there's not a whole lot more I can do to improve airflow. The biggest problem is the front intake fans push the disks back into the PCI cards which cause restricted airflow.. Either I remove the front fans to increase airflow (but then no longer have front intake), or I retain front intake but have restricted airflow.. I'm also looking at getting a module power supply as there is quite a clump of cables in the disk bay that is further restricting air flow from front to rear.



Even when not overclocked and running at 266FSB with 1.30vcore, the core temps hit 70C under load, ~46C at idle.

When overclocked to 400FSB, with 1.34vcore (after my MB's vdroop), while the system is perfectly stable, my temperatures are WAY too high.


Idle:

25C Tcase ("CPU")
~50C Tjunction (TAT reports ~53C on each core, SpeedFan and CoreTemp show about 48C)


With TAT running at 100% on each CPU:


60C Tcase
86C Tjunction




I deliberately wanted to hit 85C today because I wanted to know if the CPU would get throttled. The reason for this is I'm starting to suspect the core temperatures are not being reported correctly.

I don't understand how I can get a 26C difference between Tcase ("CPU") and Tjunction (the cores).

I'm puzzled why my system didn't get throttled at 85C.. CoreTemp shows my "Tjunction" throttle at 100C (delta to Tjunction uses the 100C figure).. Is this accurate, or does the fact it didn't throttle at 85C mean that the core temperatures are not in fact that hot?

I was getting similar temperatures with the stock Intel cooler, so I bought the Big Typhoon and some AS5 to see if that would help.. It didn't.


The other interesting result is that as soon as I stop the TAT 100% load, all temperatures return to normal very quickly.. Within 2 seconds it's dropped 20C on Tcase and Tjunction. Within 10-15 seconds, the system is back to idle temps.

This result tells me my heatsink/cooler is doing it's job.. Is that a correct interpretation? As far as I can tell, the heatsink is seated properly. There's no movement when I try to wiggle it.

According to the guide, there should only be ~15C difference between Tcase and Tjunction.. This is all within the CPU right.. Tcase is between the cores, and Tjunction is on each core.. There's nothing I can do to change that right? Does the difference in temperature on these sensors relate to the contact with the chip and the IHS, or the thermal dissipation characteristics of the silicon?

Help

 

[auldar]

I should also say that I have the Big Typhoon on max fan speed (~2080rpm - sadly very loud), and I'm using Vista..

Currently the case fans are set to Optimal Q-fan setting, although I've also cranked them up to max and it doesn't help either..

 

[auldar]

Results

Tcase = 25C Idle & 60C Load
Tjunction = 53C Idle & 86C Load, Hottest Core

Variables

Ambient = ~20C
Chipset = P965
C2D = E6300
CPU Cooler = Thermaltake Big Typhoon
Frequency = 2.8Ghz
Load = TAT @100% for 5 mins
Motherboard = P5B Deluxe Wifi
Vcore = 1.34vcore (after vdroop)


Thermal monitor did not activate


Using passive cooling on my 7600GS

3 HDD

 

[SirCrono]

I had a very similar problem on my very similar e6300, wild variations under load, very fast temp drop when load stops.
I was going nuts about it and one day I decidede to remove the side of my case to see if this would improve things, it didn't, but that lead to me pressing the HSF towards the cpu and suddenly core temp showed a very big decrease in temps (about 15°C), I released the HSF and the temps spiked up again and so I discovered the HSF wasn't properly seated, I removed it, reaplied AS5, reseated it and voila, decent temps (38 idle, 55 dual prime95)
Sry for the long story.
try reseating the HSF, don't be afraid to press it a little against the mobo (do not push it with your hand while the pc is running, it's dangerous)
Hope it helps

 

[CompuTronix]

auldar, thanks for the text and for additionally providing info in the proper format. I see 2 red flags. Tjunction is probably offset by +10c, but more importantly, both your Tcase and Tjunction Idle to Load Delta's are 35 and 33 degrees repectively, and are far outside the 25 degree spec. This typically indicates any combination of 4 problems:

(1) An improperly seated CPU cooler.

(2) Inadequate computer case cooling.

(3) A concave CPU Integrated Heat Spreader.

(4) A concave CPU cooler heat sinc.

From the Guide:

Specifications

Idle to Load Delta Max = 25c

Parameters

(H) Idle to Load Delta should not exceed ~ 25c.

Troubleshooting

(I) C2D’s manufactured with concave Integrated Heat Spreaders may report high Deltas and temps.

Since you've dicussed items 1 & 2, I would suggest that you look into items 3 & 4.

Hope this helps,

Comp 8)