T9900 undervolting question

I just purchased a T9900 and installed it with AS5. I know AS5 takes several days to cure but I can't help ignoring my current thermal result.

Lenovo T500
T9900
Ati 3650 chip
4mb ram

Running Prime95, speedfan and rightmark cpu.
Currently undervolted to 1.2V, speedfan is showing:
Core 0 78C
Core 1 84C
Temp 1 63C (I'm assuming this is the 3650 ati chip)

It seems to me that the chip is overall running too hot even with the mild undervolt. What voltages are your T9900 chips able to reach? Intel states the VID rating is 1.050V-1.2125V. My chip's default voltage according to rightmarkcpu is 1.375V which is quite higher intel's rating. Not sure why there is such a discrepancy. Should I be undervolting to 0.15V lower than 1.375 or 1.2125?

 

My T9900 has been running a bit hot too.

Idling around 50C. I don't really care since these can withstand upto 105C.

Go as much as you can. There is no limit for undervolting as long as your computer runs stable.


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Your temps are not worth any concern.

I'm not sure how cool you expect a 3.06Ghz chip to run, but 78/84 are well within the range of normal operation.

 

great. nothing to sweat about. I'll repost in a few days after the as5 cures.

 

Prime95 temps around 85C are perfectly acceptable.

 

i was running into different issues with the as5 and my t7600, i tried all the different applictions the dot, the vertical line, the spreading method.

and i was under the impression from alot of other instructions and different videos ive watched that thinner is better.

well after about 7 different applictions of trying different variations of applying the as5. i found personally i got better temps using the spread method and using a little more as5 and eventually i got great temps about 28c idle and mid 30s doing some video downloading and surfing the net.

i guess it really depends on the heatsink, the number of fans, and how and how much you use of the as5 as to what kind of temps you will get.

 

Yes CPU temp can vary with:

Ambiant temperature.
Heatsink design.
Fan size and speed.
Vent size and design.
Voltage.
Chip quality.
Temperature sensor accuracy.
Type of thermal paste used and application technique.

 

I've switched over to unclewebb's throttle stop instead of cpumark dt the confusing multiplier. The T9900 uses 11.5x which is confusing to set up with cpumark. Anyhow, I ran Prime95 at 1.1V and my system did reboot after several hours. I'm now rerunning it at 1.125V and it has not yet crashed. My temps have also greatly improved: Core0 69C, Core 1 71C.

I applied a tiny amt of AS5 and thinly had it spread. Did this with the GPU, CPU and Northbridge.

 

If the Northbridge had a thermal pad on it, you should have left it there.

 

It depends. If there is good contact without it, there is no reason not to replace the thermal pad.

 

You forgot the most important one my friend:
The room temprature!
Don't just laugh, it has a big role in this case...

 

Ambient temperature was at the top of his list.

 

My fault, but I would still call it room temprature More, non-super-duper-english-good friendly

 

Oh, sorry. I didn't see your location!

 

What if you run it outside?

 

If I do that here in Norway, I think my laptop will actually freeze. If I sit outside in Turkey, well, I allready can smell the dinner...

 

Ambient Tempurature is 20C

 

if u use ICD7 , your results wll be way better.. basically AS5 is not good for newer and hotter CPU's.. i have ICD 7 and my i7-740qm doesn't break 75C... on full load... and tunjay , if i sit outside in UK now , my laptop would freeze/crack and get snowed on.. sadly no snow yet... it has to snow everywhere else but not in london brb..

 

Updated...
At 1.1Volt, my cores temp are pretty consistent full load at:
speedfan 74/75C
throttlestop 80/81C

 

No, while room temperature plays a role the internal laptop ambient temperature is the most important one. It is this temperature that all the internal components are referenced to.

 

What is this supposed to mean? Ambient temperature is room temperature. You must be confused about something here.

 

What he is saying is true for desktop heatsinks. That it's fairer to use internal case temperature as a reference rather than the room temperature.

However with laptops the case/ventilation is all part of the thermal performance of the machine so it's better to use room temperature.

 

Ambient temperature when used for thermal performance is the local ambient temperature not room temperature (the key word is local)

Typical Intel DoT (this example taken from the 965 mobile chipset TDG).


When you raise the back of the laptop you might find you CPU temperature drops by a few degrees. It is the internal local ambient temperature that has dropped and caused this, room temperature stays unchanged. A laptop cooler should also reduce the internal temps even more so.


HWMonitor used to show the local ambient temperature.

FYI room ambient here is 32C but while idle the internal local ambient is ~39C. Notice how at idle the CPU and GPU are fairly close to local ambient not room temperature. Also be aware that the C2D DTS has been adjusted to give somewhere near correct values, without correction the cores would be reading much lower than true at idle.

Ideally it would be better to have several sensors in different locations but because of extra cost coupled with most people not even aware that such a temperature sensor might exist on their laptop that's not likely to happen.


Lets see what happens with some Linpack load.

The differential reading is the difference between local ambient and the CPU. It can be seen to reach its high value quite quickly (35C) however the CPU is also heating up the internal local ambient temperature as well, now at 42C. The GPU shares the same heat-pipe as the CPU so as the heat-pipe gets hotter so does the GPU even though the GPU is not doing any extra work.


2 minutes into high load

Even though the CPU is still generating the same heat (35C) the local ambient has now risen ~10C from it's idle temp resulting in even higher temps of the CPU. Many other internal components that share the same internal void will have risen in temperature too by this amount or close to it. If the local ambient was the same temperature as the room ambient (32C) then the CPU would only be somewhere around ~67C (35C + 32C) not ~83C.


Summary

1. End of high load. CPU temperature drops off quite quickly.
2. Once CPU temp falls to heat-pipe temperature the GPU starts dropping temperature as well.
3. Once the heat-pipe temp falls to the local ambient temp all components start dropping in temperature.
4. Differential showing CPU thermal operation without effects of external temps.

Considering the compact and enclosed space of laptops the internal ambient temperature plays a major part in thermal performance, probably more so than desktops.

TBH I'm not so keen on writing these long explanations and still probably not being understood. Better I should give up trying and leave it to people like Unclewebb.