Difference of 2c with cpu fan at 100% and 0%

zagood

Diamond Member
Mar 28, 2005
4,102
0
71
Made some new case cuts, redid wiring, and swapped out thermal paste this weekend. It's been pretty warm so differences of higher temps are inconclusive, but saw something I've never seen before.

Sensor low range is 37c/32c (Core 0/Core1), which is also idle temps.

Running Prime 95 with fans @7v, CPU temps ramped up to 51c on both cores. That's a little higher than it was before the changes, and understandable given ambient of about 80f, so just to be safe I took the CPU fan to 12v.

Load temp stayed at 51c.

I thought, hmmm, I normally get a good 3c+ difference when I crank up the CPU fan...turned the case fans all the way up as well and no change (slight fluctuations of course).

Just messing around, I turned the fan off completely. The temperature slowly climbed to 53c and stayed there. This is running small FFTs on both cores.

WTF?

So here's the questions...

1. Could the ineffectiveness of raising the fan speed be caused by improper TIM application? I don't want to disassemble again and take the motherboard out for the backplate just to re-apply TIM. I know a few tricks for not removing the motherboard but they're kind of a pain.

2. Does this processor really stay that cool or is something borked with the sensors?

3. Should I just run passive?

4. Anything else I should test?

Specs...

e5200 @ 3.5ghz - 333x10.5 - 1.325v / TRUE + S-flex 1600rpm
ep45-ud3p F6 bios
4x1gb DDR2-800 5:4 (400mhz) / 4-4-4-12 2.0v
8800GTS 640mb / HR-03GT + Panaflo 92mm
Antec 300
2xYL d12sl-12 front intake
1x 800rpm noctua side intake
1x S-flex 1600rpm exhaust
1x stock 140mm top exhaust
All fans except noctua are on a Sunbeam Rheobus
Corsair 620HX
Vista x64
Temps via RealTemp plugin in RivaTuner - verified with full RealTemp and Speedfan (albeit constant 5c difference in Speedfan)
TIM consultants 0098 for CPU, ceramique for GPU.

Thanks. I'll post the case cuts (a little sloppy so I hesitate to call them mods) when I get some C-channel to finish them off and take more pics.

-z
 

CurseTheSky

Diamond Member
Oct 21, 2006
5,401
2
0
1. Yes, but I would judge that based on what your temperatures were before these changes. If the ambient temp was similar (let's say, +/- 5 degrees F) and your CPU was quite a bit cooler before you made these changes, you probably need to remount the cooler and reapply TIM. Since you're using a cooler with a backplate, I'd guess you're probably fine, though.

2. Intels Core 2 dual cores run decently cool. See below.

3. The Antec 300 / 900 / 1200 / etc. have an open air design, and are generally pretty good at cooling. I'm not as familiar with the 300, but I'm guessing there are fans near the CPU anyway. Those are probably doing almost as good of a job as the fan directly on the heatsink. I started out with a fan on my Sunbeam Core Contact Freezer, but took it off after I realized it did basically nothing with the two case fans right next to the heatsink.

4. Did one of the cuts you made in the case screw up the air flow by any chance? Do get significantly better (or worse) temperatures with the side panel off? What about with the side panel off and a desk fan blowing into the case?
 

yh125d

Diamond Member
Dec 23, 2006
6,886
0
76
For reference, I'm running my TRUE passive on my OC'd e7200 in my sig, only fan nearby is the 120mm rear exhaust, ~3" away and it loads in the mid 50s
 

zagood

Diamond Member
Mar 28, 2005
4,102
0
71
CTS: 300 is a little more closed than the others, but the heatsink is right up next to the 140mm top exhaust and fairly close to the rear exhaust. That may have something to do with it.

Cuts were all planned out, if anything there's better (or at least more controlled) airflow. Side panel off is negligable difference.
 

zagood

Diamond Member
Mar 28, 2005
4,102
0
71
Friggin heat wave this week - so I'm holding off on additional testing since ambients are all over the place.