How much can I undervolt and underclock a T7300?

Hi,
since I am gonna cancel my laptop order due to a delay, I am also reconsidering my configuration to extend battery life and possibly save a few bucks.

I am not interested in overclocking; on the contrary, I would lilke to slower the CPU down, also reducing its voltage, in order to save power and reduce the heat produced.

How far down can a Core 2 Duo T7300 go?
The last CPU I bought (for my desktop) is a P4 1.6 GHz Northwood, so I need to catch up a little bit in tech updates : ).
Specifically, I do not know if these new 'speedstep' processor (Core 2 Duo) can be manually slowed down and to what extent.

Basically, what I would like to have is a slow and cool processor when I am reading, writing, browsing, and a fast beast when I have to do some heavy number crunching. I have this hunch that -for example when reading a pdf - a T7300 slowed down by speedstep is still hotter than a T5470 slowed down by SpeedStep.

Am I wrong?

Any opinion?

 

I have a T5200, and it is stable at 0.950V, which is the lowest setting on RMClock. The original voltage was 1.175V. I believe since it is the on the lowest setting, when the multipliers change to a lower one, I don't save any power so I always use maximal performance.

 

My T7300 has a default voltage of 1.25V for the 10x (2GHz) setting. However, I have been running it 1.05V max for the past week or so without problem but it falls over at 1.0V.

You need to be running something which fully loads both cores of the CPU. I use two instances of the Prime95 torture test and then you drop the voltage gradually until either the system crashes of Prime95 reports an error. The rule of thumb is to put the voltage back up two steps and then do a long (minimum overnight) test under full load to confirm the stability. I would suggest that you go straight to 1.10V then step down gradually from there.

John

 

Thanks for your answer.
How much cooler is it, downvolted to 0.950?
(I am now planning to go for the T5470 on my Vostro. The money I save, along with those saved for the 8600 -> 8400 downgrade will be used to bring more power into my future desktop)

"Power to the desktop! Long life the laptop battery!"

 

Read the full content of this Article: http://www.dev.notebookreview.com/news/foremay-breaks-the-2tb-ssd-barrier-your-bank-account/

 

My max temperature is now less than 60c, before it was 80+.
My fan cools 50% faster and less

 

The temperature reduction by undervolting is usually at least 10C under full load conditions. The actual drop varies depending on the cooling system and whether you have a fully-loaded GPU sharing the same cooling system.

I have seen both reduced voltage and consequent less fan noise. There is no significant temperature drop under low load conditions because the Core series CPU's have their lower voltage locked.

John

 

Read the full content of this Article: http://www.dev.notebookreview.com/news/trendnets-new-tew-805ub-brings-high-speed-802-11ac-to-usb3-0/

 

This is more than I expected! Good news, at last!

Therefore there won't be any significant difference between a T5470 and a T7300 during light usage? Or does this apply to the deepest sleep state only (i.e. while the laptop isn't used at all)?

I cannot find any Intel datasheet referring to the T5470. I have the 31674502.pdf and 31674503.pdf papers from Intel, but I can't find any reference to the T5470. And yet I recall to have read that its maximum power consumption was some 10 w lower than its T7x00 counterparts (25W vs. 35W).
Anyone has more info on the power needed bt that processor?

I am now torn between the T5470 and the T7100 (less than 15$ difference), the main question being not speed but power (battery life).

(Oh, and I have no idea whatsoever of the benefits of hardware virtualization)

 

I take it it can be done by software, since the new Speedstep processors can adapt their speed and voltage on the go. Programs like NHC ( http://www.pbus-167.com/) are popular under Windows. I, too, would like to know an equivalent program running under Linux

At the moment I don't have a processor of that breed, so I can't give you any more infos.

 

well for my laptop running the T7200 CPU
the current voltage settings for my multipliers goes as follows

1-11 is at .95 volts
12th multipyer is at 1.06.. * i could go 1.05 but i tend to not notice that .1 volt anyway xD*

as for overclocking i am not sure if you can do it as of yet >.< and overclocking may interfere with your OCing depending how hard you push it

I personaly think that just leaving it stock is more then enough juice out that lemon if you catch my drift

edit* buy more ram it will reduce the hard drives load and will cool your harddrive... i am sure you know this but just wanted to say*

 

Wikipedia contains more info about the range of Intel CPUs than Intel itself provides. You will see that the T5470 is a 34W part. If it used less power then Intel would charge more money.

I would expect no significant difference in power consumption under light load. I do not know if the T5470 and similar CPUs support dynamic FSB switching and dynamic acceleration technology (sections 2.2.1 and 2.2.2 of Intel document 31674503.pdf).

John

 

Indeed. It probably was a mistake of some sort then. I have not been able to find that page again to check that out. All I remember is that it reported a 34 (or 35) W thermal profile for both processors, but it had different figures for the electrical power needed to run under full load.
Could it be something related with hardware virtualization?

At any rate, I no longer need to worry since Dell shipped my Vostro yesterday, right when I called to cancel the order. (I have to update my sign!)

I am glad to know that
In the Dell forum a user with a T300 and GeForce 8600M GT has reported some 5+ hrs of battery life under light usage and power saving mode.
So this seems to further confirm your statement.

Those features are supported, AFAIK.

Thanks fro your asnwers, they were very informative.

 

From another thread ( http://forum.notebookreview.com/showpost.php?p=2613751&postcount=34):

Hell, I'm confused...

 

Unfortunately, the voltage variations between individual CPUs make such comparisons difficult. I'm sure the die size is the same. The T5470 just has part of the cache disabled and, for the same voltage, should therefore draw a little less power.

All these CPUs run at the same minimum speed: 1.2GHz under normal operation and 800MHz (Intel SLFM mode) if the BIOS supports the SLFM mode. The preset voltage for operation at those frequencies is hard-coded into each chip during manufacture. Comparison between the power requirements of these two CPUs would therefore need two with the same voltages.

John

 

According to Intel Spec for T7300, the lowest voltage for the CPU is 1.0375 V.
http://processorfinder.intel.com/details.aspx?sSpec=SLA3P
http://processorfinder.intel.com/details.aspx?sSpec=SLA45