Concerning Core Voltage and Usage

Has anyone here attempted to sucessfully undervolt their SZ's?
What are the reprecussions of undervolting, and is the guide featured on this site fully applicable to our Core Duo machines?

On a related note,

In Everest, my voltage is listed at 0.950 - 1.262, and it seems as though Core #1 is getting a lot more usage and is at a much higher temp that Core #2. Could anyone explain/solve this?

 

Undervolting a Yonah based computer is easily doable but the benefits are slim.

The lowest you can adjust the voltage for a Yonah cpu is 0.950 volts (Hardware limited), which the CPU automatically drops to when light/no usage. So the only aspect to really gain is to undervolt when CPU is under full load.

Previous version, the Dothan series (Pentium-M) benefited a lot more from undervolting because the standard voltage at idle was roughly 0.988 volts. Using utilities such as RMClock, a user could undervolt the Dothan chip to 0.700 volts (Lowest possible limited by hardware) and run stable as well as lowering the volts when on full load.

Lot of people speculate Intel put the core minimum at 0.950 volts because allowing people to undervolt would hurt their ULV market (Ultra Low Voltage).

As for your cores on Yonah, I'm not sure why one core gets more usage then other... XP should load balance by default. But if assuming the loads are equal it is not unusual for one core to be more hot then the other. The cores although from the same wafer fabrication may have small differences which inherently may cause it to use a little more energy or be unstable at a given speed so they rate it safe at X Ghz and release it as such.

So while core #1 may be able to run stable at say 2.16 Ghz, the other (Core #2) may not and runs stable at 1.86 GHz, so they market that CPU as 1.86 GHz. This would ultimately mean that Core #1 will be cooler running at 1.86 then Core #2.

If this sounds confusing just ask for clarification.

 

You've responded to my topics before-- thank you ^_^

Everest says that my SZ's voltage is currently 1.26 (max). And, it's always 1.26, no matter how many memory/cpu intensive programs I open. My system is currently maximum clocked at 1,833 Mhz. In addition, core #1 is at 39 degrees C and core #2 is at 35 degrees C (with Targus Cooling Pad). All I have open are two Firefox windows.

I just wanted to ask if there would be really noticable performance differences in speed, in addition to stability, if I undervolt.

And, can the program in the featured article be used to undervolt my Yonah processor? Should I do a google search? Would you be so kind as to recommend one, if possbile?

 

I believe 1.26 volts is the max, I tested mine a minute ago and running superpi on each core capped it at 100% usage at 1.263 volts.

Regarding system speed, there will be no difference if its run at the 1.263 volts or underclocked. The main things the voltage affects is system stability and heat. Running at too low of a voltage will result in system stability issues, not enough power to keep the processor going correctly. While going over whats needed will create excess heat because the extra energy is just converted to heat. (Most CPUs get more energy then they need, but its a standardized volt setting that will work with all CPUs)

The thing to keep in mind if you wish to underclock is that you must slowly lower the voltage and test for system stability by running CPU intensive programs that stress both cores.

Program to use, Rmclock is nice but I believe that NHC is probably better for Core Duos (Yonah). I personally have not used either one with the SZ series, just what I have heard from others. NHC is Notebook Hardware Control, previously known as Centrino Hardware Control. As for program to use to stress test, Prime95 is good and what I use but I've also read others use programs such as Rosetta @home. (A tip for when you stress test the cores, open two of the same program and use task manager to specify one program to run on one core and the second program on the second core)

My personal experience with Rmclock is on my older laptop, Vaio S360. Rmclock worked really well with that one, a Pentium-M based.

 

I think Lyshen used the word 'underclock' incorrectly. I think he meant 'undervolt' because underclocking actually reduces the frequency and speed of the chip (but undervolt doesn't).

 

lol, this topic is ancient
Yeah, I tried underclocking regardless--didn't do anything for my battery life.
Undervolting went very well, though.

 

Haha yes I meant undervolt.