Swapping X41T 758 processor with ULV 773

[thinklogic]

http://ark.intel.com/Compare.aspx?ids=27611,27604

It appears the Pentium ULV 773 processor is a direct drop in for the X41T.

I am currently running a Pentium M 758 1.5Ghz processor. However, I'd like to switch over to the Pentium M 773 1.3Ghz, as it drops the operating wattage by 2 watts, which will give a nice battery boost. Anyone ever done this before? Is the CPU on these X41Ts possible to remove? Would this result in a bricked laptop?

[Vempele]

The processors in the X series are soldered.

[sjthinkpader]

There are a few ULV versions in the X40 lineup. I have the 1.0Ghz version and it is very low power.

[thinklogic]

The processors in the X series are soldered.

Well this answers THAT question.

Unless there's any certified professional desolderers for hire I doubt I'll be attempting this.

[eyestrain]

There are a few ULV versions in the X40 lineup. I have the 1.0Ghz version and it is very low power.

Does the fan come on with that ULV X40?

I'm surprised how loud my LV X40 is. Even though it has Intel graphics (like all X4x). I guess because it's so small.

Other than the noise I like it a lot.

Haven't gotten around to undervolting yet, might run much cooler, since the one I have is a Dothan, known to be very undervoltable. Got my T42p down to .7v at 600mhz (and surprisingly quiet and cool) so I'd expect the LV chip to hit .7v at 600 too.

[thinklogic]

Apparently many X41T tablets out there already have a ULV processor in the form of the Intel Pentium M Ultra Low Voltage 753 (1.2GHz).
http://www-307.ibm.com/pc/support/site. ... 60014.html
When I'm ready I might sell this one and go ULV

[eyestrain]

Just because it's available doesn't mean there's many out there.

I've been looking for a Dothan 1.1 X40 cheap, or a Dothan 1.2 X41t cheap for awhile now, with no luck.

The reason I want the ULV is because I want the machine to be low voltage without having to undervolt. Linux.

If you don't mind undervolting yourself, very easy in Windows, harder in Linux, then you can likely make your own ULV chip, Exactly as low voltage as the ULV chip, maybe better, and with the added advantage of being able to reach higher speeds if you wish to allow the CPU to do so.

See the last post in this thread http://forum.thinkpads.com/viewtopic.ph ... 38#p518838

Both the ULV and the regular chip (or in your case, LV chip) went down to .7V at lowest speed. But at 1.1ghz, the regular chip was lower voltage!

As fortexg says, "So, which CPU is really the ULV now?"

In Windows, NHC or RMclock can do this for you with your X41t, X41, or X40, or many other computers, Pentium M and later I believe. For C2D, CPUgenie may be better, because of a special idle state.

[thinklogic]

thank you for your good insight here. I was able to underclock my 1.5Ghz Intel Pentium M 758 to 600Mhz @ .7V!!

Serious savings there, should keep the power down to a minimum without any further $$$ investment. If I run something with a heavy load of course it can bump it back up. I use the tablet a lot for PDF reading, and having 600Mhz on tap is a nice commodity

[eyestrain]

Glad it worked!

How often does the fan come on now? I haven't got windows on my X41t or X40 yet to undervolt.

Do you have it forced to stay at 600mhz? If you have a Kill-a-watt to test, or software that can test, you could try using speedstep to allow the cpu to bump up as needed, and see if it's worthwhile. There is a philosophy that it is actually power saving, to use the higher cpu state when cpu is doing work, so you can get the cpu idle quicker. 600mhz and working uses more power than 600mhz and idle. So, if you also undervolt at 1.5ghz, and probably steps along the way, and let speedstep happen, you might save battery compared to forced 600mhz. And it will run faster.

If you see a low V at 600 (.7, you do ) and still low for freq near there, but a big jump in V at some point, you could consider cutting off there. For extreme example, if 1.3ghz is .8v, but 1.4ghz is 1.1v, then you might want to try speedstep on all speeds up to 1.3ghz. (Making up numbers, but direction should be correct.)

Maybe someone knows?: I believe that .7v at 600mhz, at 100% load, uses less power than .7v at 700mhz at 100% load. But I don't know how much. Dropping V is very important, energy is proportional to the square of V. What about freq? How about at low load? Of course at high load this comes back to the point of maybe being good to use high freq to get back to idle sooner, where the cpu goes into very low power mode until next wakeup.

Which brings up another power saver I haven't tried yet: finding and eliminating the causes of your particular computer's (OS, software, hardware) cpu wakeups. In Linux, there's Powertop and a simple power management program I think comes standard with Ubuntu, you could add to any Linux. If interested, ask me for the name.