Any advantage to undervolting a 64bit/low-voltage/1.6Ghz X61s?

[Libre_ME]

Recently I dug out an older Garmin GPS that I need Windows for to install maps onto this device. The dock for my three X6x macines has the required serial/rs-232-port. I haven't used Windows for years, but I found a Windows 7 disc and so I put the original spec. motherboard back into the X61s, I had a Librebooted X60-tablet board in it, installed Win-7 and while updating the OS I read a review on the 51nb-X210, where the guy undervolted his i7-cpu and got a big increase in performanceat at the top end from the cpu. Is there any kind of performance increase advatage with a low-voltage cpu? As it is, I have no complaints at all with the current performance that I get with the l7500 board. It's just a curiosity, after reading about the performance increase in the writer's X210. If indeed there is anything to be gained could someone share any starting point values so that it can get me close. As I understand it, each and every individual cpu, even from the same batch will require one to find it's individual best settings. I have absolutely zero experience with this subject, but I thought that it might be worth looking into further if there really is some sort of performance increase.

[super_hkg]

Ummmm

I own a T61 and a X61 and both of them are running in a lower voltage. Same clock speed but lower voltage. It can be lower for around 10 degrees in full load.

I don't think you can have advantage for L7500 for further lower the voltage as L7500 come with lower clock rate and also low voltage

[axur-delmeria]

The direct results of undervolting the CPU are reduced power consumption and lower temperatures. In the case of the X210, this allows the Core i7 to stay at Turbo Boost speeds for longer periods, resulting in increased performance.

However, the Core 2 Duo L7500 does not have Turbo Boost-- it has Turbo Boost's rather lame predecessor called Intel Dynamic Acceleration (IDA for short).

To elaborate:

The Core i7-8550U in the X210 has a base clock of 1.8GHz and a max Turbo Boost clock of 4.0GHz. As long as the Core i7 doesn't hit the temperature or thermal design limit, it will happily run at 4.0GHz. That's why undervolting results in improved performance.

In contrast, the Core 2 Duo L7500 has a base clock of 1.6GHz and a IDA boost clock of... 1.8GHz.
As you can see, it's barely an improvement.

For older processors, the impetus for undervolting is to lower CPU temps and increase battery life. This is essential for the regular X61 but not so much for your X61s, since it already uses a low-voltage CPU. However, there's nothing stopping you from undervolting your Core 2 Duo L7500 -- I've done so in my old X61T.

[Shredder11]

My X61 has the T7500 CPU and as such runs very hot all the time. It was really bad when I first got it, and I took it apart and cleaned the fan thoroughly and re-applied thermal paste to the CPU. I also installed a supposedly cooler running WiFi card, but not sure if that made any difference to the overall temperatures.

However I would like to maybe try undervolting a little to see if this helps with the deafening roar of the fan. Is it worth doing on the T series of this CPU? My temps when running software or browsing can be between 70°C and 90°C and higher sometimes. This is using TPfan set to run the fan at nearly 6000rpm, to try and prevent the machine from melting itself.

[axur-delmeria]

Is it worth doing on the T series of this CPU?

Yes, by all means, undervolt it.

I've had two X61's, both Penryns (T8100 and T9300), which run cooler than the Merom T7xxx CPUs, and had to undervolt both to keep them at comfortable temperatures.

[Screamer]

I own a T61 and a X61 and both of them are running in a lower voltage. Same clock speed but lower voltage. It can be lower for around 10 degrees in full load.

I don't think you can have advantage for L7500 for further lower the voltage as L7500 come with lower clock rate and also low voltage

You can. The L7500 can be further undervolted without any problems, just like the rest of the other Core 2 processors. For clarification, the L7500 is not a processor that has been undervolted from the factory. It was produced and tested to run at a certain clock speed with a voltage lower than the standard voltage processors; the factory uses the same method of production without the lower voltage binning on the standard voltage processors. This is the only difference that separates it from the standard voltage processors.

An undervolt would mean that the processor is operating under its factory rated voltage, so undervolting the L7500 is similar to undervolting a X7800 and so on. It probably wouldn't be too noticeable with the lower voltage though, but the advantage still exists (until you hit a voltage wall in the process).

[Libre_ME]

Thank you for your replies and for the great details shared! The l7500 board, I have only seen it get to 50c temp. I just aquired another X60 with T7200 cpu and I've seen it go to 70c in testing. the bios is Libreboot and it's running Linux. As far as I can tell I can not undervolt it in linux, although the tools look available to do so.

[axur-delmeria]

Thank you for your replies and for the great details shared! The l7500 board, I have only seen it get to 50c temp. I just aquired another X60 with T7200 cpu and I've seen it go to 70c in testing. the bios is Libreboot and it's running Linux. As far as I can tell I can not undervolt it in linux, although the tools look available to do so.

Do you have the linux phc kernel modules compiled and loaded?

[Libre_ME]

Thanks for pointing me to that! Unfortunately if it requires compiling, I'm out. I've never compiled anything before. I also noted that the last update to their web page is 2014. Does this mean that they have lost interest in their own project?

[axur-delmeria]

Thanks for pointing me to that! Unfortunately if it requires compiling, I'm out. I've never compiled anything before. I also noted that the last update to their web page is 2014. Does this mean that they have lost interest in their own project?

The problem is that Intel locked down the voltage controls when the mobile Core i3/i5/i7 came out, which lasted until the 3rd generation (Ivy Bridge).

PHC is still being updated in order to compile against the latest kernels. Here's the download page: http://www.linux-phc.org/forum/viewtopic.php?f=7&t=267

What Linux distro are you using? PHC has the means to create packages for Debian (and quite possibly its derivatives) and Red Hat (or any distro using RPM packages).

I made a post a few months ago about compiling PHC: viewtopic.php?f=30&t=126067&hilit=phc#p819870, though as I explained in that post, I haven't tried compiling it in a long while.