Asus P5B and Core 2 Duo E6700 cooling mystery

donu · Post by **donu** » Fri Mar 30, 2007 4:33 pm

I'm not sure whats going on. Perhaps you do?

My system:
- motherboard: Asus P5B Deluxe
- CPU: Core 2 Duo E6700
- CPU cooler: Noctua NH-U 12F with Noctua NF-S12 120mm fan
- RAM: Crucial Ballistix DDR2 PC2-6400 2GB
- 1st video card: GIGABYTE GV-NX76T256D-RH 7600GT (Rev. 3.0)
- 2nd video card: GIGABYTE GV-NX76T256D-RH 7600GT
- case: Antec P180
- fans: Noctua NF-S12 120mm fan pushing in front vent, another pushing out back vent
- PSU: Zalman ZM460B-APS
- monitors: 2 Dell 2007FP, 1 Dell 2001FP
- operating system: Microsoft Vista Ultimate
- no overclocking
- very neat cabling job

Fact 1:
My CPU core temperatures as reported by TAT (Intel Thernal Analysis Tool) are:
43 at idle, 65 at max load (in 22 degree room).

Fact 2:
If I take the side off the case and aim a window fan into the case, the CPU core temperatures (TAT) are:
41 at idle, 60 at max load (in 22 degree room).

Fact 3:
The northbridge heatsink is too hot to hold my finger on.
The same is true of the southbridge heatsink.
The same is true of the heat pipes on the 2nd video card.
The CPU heatsink is barely warm.

Fact 4:
I've tried 3 different CPU heatsinks and 3 different thermal pastes, and the results are alway similar, so I don't think I have a CPU heatsink mounting problem.

Fact 5:
This thread
http://vip.asus.com/forum/view.aspx?SLa ... 1&count=17
in the Asus forum for my motherboard suggests that the CPU temperatures may not be reported accurately.

Fact 6:
With the case side off and the window fan blowing in, and TAT at 100% workload, the northbridge heatsink, the southbridge heatsink and the video card heat pipes are all 'touchable'.

Question 1:
Since my CPU heatsink is barely warm, does that mean its not doing its job? Or does it mean that the CPU isn't generating enough heat to warm up the CPU heatsink?

Question 2:
Do you think I have a cooling problem? Or a temperature reporting problem?

All responses are appreciated.

Plissken · Post by **Plissken** » Fri Mar 30, 2007 5:14 pm

My system is nearly the same as yours, with the exception of CPU, and I get 68C TAT under full load (reported by TAT) with case closed in 21C ambient. You should check with a couple other programs (SpeedFan, CoreTemp) to see if they agree. The way I look at it: I'm still 32C away from throttling (assuming 100C Tjunctionmax), so no big deal.

marc2 · Post by **marc2** » Fri Mar 30, 2007 5:26 pm

Hi :

My system is also similar.
I don't have any fan in front.
The CPU fan and the rear fan are running at 800 rpm.
The CPU temperature is 34C at low load and 44C with CPUBURN running.
Temps are the same with the ASUS monitor or with SPEEDFAN.

I think that those temps monitoring are not very accurate.
By the way, SPEEDFAN shows 120C for AUX ! What is AUX ? I don't see any smoke out of the box ...

donu · Post by **donu** » Fri Mar 30, 2007 5:33 pm

Plissken wrote:You should check with a couple other programs (SpeedFan, CoreTemp) to see if they agree.

SpeedFan reports temperatures 4 degrees lower than TAT.
CoreTemp does the same thing.

Plissken · Post by **Plissken** » Fri Mar 30, 2007 5:43 pm

TAT is pretty old, AFAIK it hasn't been updated since the Core2Duos were released. It's great for stressing but I'm not sure about its temperature measurement.
The newest Core Temp release gives the delta to max Tjunction, which is all that really matters.

skidrow · Post by **skidrow** » Sat Mar 31, 2007 12:11 am

Hmmm ...
You make no mention of the top exhaust fan in your P180. Have you turned it off? Still the original Antec TriCool? Covered up the hole?

donu · Post by **donu** » Sat Mar 31, 2007 5:02 am

skidrow wrote:You make no mention of the top exhaust fan in your P180. Have you turned it off? Still the original Antec TriCool? Covered up the hole?

Top exhaust vent has no fan and is not covered. I tried installing an exhaust fan and it made no difference. I tried covering the hole and temps went up slightly.

Post by **CA_Steve** » Sat Mar 31, 2007 6:09 am

My take:

- I think your CPU cooler is working just fine. A decent heatsink/fan combo will keep the heatsink cool to touch. TAT gives consistant results - especially to compare to others with similar cores. My e4300 overclocked to 2.5GHz idles at 37-40C and runs at 58-60C at 100% TAT load. This is with a Ninja and the much maligned push pins.

- Your hot-to-touch heatsinks on the NB, SB, and vid card mean they are conducting the heat well. But, since they cool off when you throw a fan on them, simply means more airflow = better cooling.

skidrow · Post by **skidrow** » Sat Mar 31, 2007 12:29 pm

Top exhaust vent has no fan and is not covered. I tried installing an exhaust fan and it made no difference. I tried covering the hole and temps went up slightly.

OK, good. I have much the same rig so here's my advice:

First of all regarding overall temps. reduce the voltages in the bios by getting them off "Auto". My P5B-E and 6300 with a FSB of 460 have these but your system will of course be slightly different:

Memory Voltage: 1.80 (Lowest "Manual" Setting)
CPU VCore: 1.375 (Very Low "Manual" Setting)
FSB: 1.200 (Lowest "Manual" Setting)

Note that you have more options available on your Deluxe version that I do.

donu · Post by **donu** » Sat Mar 31, 2007 1:11 pm

skidrow wrote:Memory Voltage: 1.80 (Lowest "Manual" Setting)
CPU VCore: 1.375 (Very Low "Manual" Setting)
FSB: 1.200 (Lowest "Manual" Setting)

I'll give it a try, but before I do, why?
Pardon my ignorance on this.
Thanks for your help.

skidrow · Post by **skidrow** » Sat Mar 31, 2007 2:16 pm

I'll give it a try, but before I do, why?
Pardon my ignorance on this.
Thanks for your help.

Sorry, I didn't explain that well.
Reducing the voltages reduces the temps. Sometimes it makes a huge difference. The default, "Auto" settings are usually too high, producing unecessary current and heat. This made a huge difference in my machine. Its overclocked a lot but the temps are lower than yours. Its not what I would call a "Silent" SPCR machine but it sure is quiet.

donu · Post by **donu** » Sat Mar 31, 2007 2:34 pm

skidrow wrote:Reducing the voltages reduces the temps.

Does reducing the voltage also slow down the computer?

skidrow wrote:Its overclocked a lot but the temps are lower than yours.

I thought overclocking meant increasing the voltage, and underclocking meant decreasing the voltage. But you say you reduced the voltage AND overclocked. I guess I have some research to do.

Thanks for your help. I'm going to try reducing the voltage now.

skidrow · Post by **skidrow** » Sat Mar 31, 2007 4:50 pm

http://forum.ncix.com/forums/index.php? ... msg1252203

"If you have enough exhaust, you will never have an overheating problem since the negative pressure ensures (most of the time) there isn't any stagnant air in the case.

A perfect way to test this is simply watch your temps for 5 minutes with the system at load or idle, then remove the side panel.
Did the temp go down? If so, stagnant air.
Did it stay the same? If so, good!
Did it go up?? If so, awesome!! The case has very strong airflow that is lost when opened, sort of like removing the tunnel in a BTX!"

jaganath · Post by **jaganath** » Sat Mar 31, 2007 6:23 pm

Does reducing the voltage also slow down the computer?

Not necessarily. some CPUs can run at stock speed (frequency) on substantially reduced voltage (eg Sempron 3200 can run at 1.8Ghz @ 1.0V, rather than the stock 1.35V). However to get really low voltages (eg 0.8V) you generally have to reduce clockspeed to get it to run stably.

I thought overclocking meant increasing the voltage, and underclocking meant decreasing the voltage.

Overclocking means increasing the CPU's effective operating frequency (usually by increasing FSB); generally an increase in voltage is required, but not always. Underclocking is the opposite.

Willy Higinbotham · Post by **Willy Higinbotham** » Mon Apr 02, 2007 8:10 am

It has been reported on this thread that Noctua fans were not recommended to be used for cooling the HSF due to their low performance when they face any backpressure.

Apparently there's something 'wrong' with Noctua fans that is yet to be found, since there are varying performance reports on their fans.

I'd try another fan on the HSF.

donu · Post by **donu** » Mon Apr 02, 2007 11:32 am

Willy Higinbotham wrote:I'd try another fan on the HSF.

Thanks for the reply.

I might try that, as I like to tinker, but as I said in my initial post in this thread, the CPU heatsink is barely warm. I don't know what I'd gain by pushing more air through it.

I still don't know whether I have a cooling problem or a temperature reporting problem.

aristide1 · Post by **aristide1** » Tue Apr 03, 2007 12:41 pm

What kind of temps are you seeing from Asus Probe? It should have been included with your mobo.

I'm running a P5B-E, E6400, 2GB DDR2 and an X1950GT card. My mid tower case has a 120 intake and exhaust and one 120 on the PS.

I am still using the Intel HS.

My mobo temps, fully loaded 2 iterations of FAH, are like 35C, and the CPU running this stuff, both at 100% utilization hovers around 42C.

What happens if you ran normal/stock voltages, not the low stuff?

Have you tried a different power supply?

What happens when you run only 1 video card?

Your hot-to-touch heatsinks on the NB, SB, and vid card mean they are conducting the heat well

A SB that's too hot to touch at idle?

What's wrong with this picture?

cmthomson · Post by **cmthomson** » Tue Apr 03, 2007 4:57 pm

Any tower CPU HSF will feel fairly cool. For example, my Ninja fin temperature was 45C when the CPU was 80C (an old Pentium D system). The temperature difference would be about 1/2 to 2/3 that (say 40 and 60) for a 6700 because it uses less power.

If any heat sink in your system is too hot to touch, you are risking a short lifetime for the chips.

A north bridge can get very hot when a tower CPU HSF is installed, because the NB HS is usually designed to catch the downwash of the stock Intel cooler. Consider fans or ducts, or an aftermarket NB HS such as the HR-05.

Also, on Asus boards, there is a feature called Hyper Path 3 (it's in the DRAM configuration section) that overclocks the NB to get lower memory latency. This should be disabled if your NB is running hot.

The stock thermal paste on Asus NB and SB heat sinks is usually crap. Especially on the SB. You should apply a good TIM, such as Arctic Silver.

The P5B has covers on the NB and SB heat sinks that need to be removed for decent cooling. These are the shiny foil things that say ASUS and DIGITAL HOME. Although they look pretty, they almost completely defeat the heat sinks. They come off easily, and can be reapplied if you ever need to RMA the board.

aristide1 · Post by **aristide1** » Tue Apr 03, 2007 6:05 pm

Core 2 Duo E6600 @ 361 (3.25 GHz),

Why stop there?

cmthomson · Post by **cmthomson** » Wed Apr 04, 2007 5:06 pm

aristide1 wrote:
Core 2 Duo E6600 @ 361 (3.25 GHz),
Why stop there?

It's limited by my memory. Also I'm running the CPU fan at a completely inaudible 590 RPM. For a while I was running at 3.33 GHz, but that memory died due to severe overvolting.

This system configuration has been totally stable for over 6 months.

Also (for those who are not early adopters) this CPU is an A628; newer E6600s run at lower voltages and overclock better.

aristide1 · Post by **aristide1** » Wed Apr 04, 2007 6:15 pm

cmthomson wrote:
aristide1 wrote:
Core 2 Duo E6600 @ 361 (3.25 GHz),
Why stop there?
It's limited by my memory. Also I'm running the CPU fan at a completely inaudible 590 RPM. For a while I was running at 3.33 GHz, but that memory died due to severe overvolting.

This system configuration has been totally stable for over 6 months.

Also (for those who are not early adopters) this CPU is an A628; newer E6600s run at lower voltages and overclock better.

I wouldn't up the VDIMM voltage any I would just try to run the memory at 5-5-5-15.

Actually I have no plans on OCing my memory, I plan on running FSB:DRAM 1:1. Mine is DDR2-800 Patriot EP 4-4-4-12.