Processor upgrade on a T42...possible?

[portsample]

Does anyone know which of the T4x had soldered pins on the processors?
I've got a T42 (2373ZMK) running a 1.7ghz processor and was wondering about the possibility of a swap. Thanks. Bye.

[ajkula66]

No, they're not soldered but socketed and hence swappable.

Your upgrade options are:

PM 745@1.8 Ghz - Intel SL7EN

PM755@2.0 Ghz - Intel SL7EM and

PM765@2.1Ghz - Intel SL7V3

[burns334]

akj or anyone else who knows, will a

M770@ 2.13Mhz SL7SL work in a T42, guys on fleabay saying they will?

[RealBlackStuff]

No, that CPU has FSB 533MT/s (is for T43/R52), and T40-T41-T42 require FSB 400MT/s.

[ajkula66]

Not properly. That's a 533Mhz from a T43, you need 400Mhz.

Have you seen this:

http://forum.thinkpads.com/viewtopic.php?f=11&t=103726

[systemBuilder]

I think it will work, and I think you guys are mistaken.

The CPU internally generates its CPU clock from the FSB clock. The CPU has a bus multiplier circuit inside. So if you buy a 2.0 Ghz CPU (pentium 755), the bus-multiplier is 5.0, and the internal CPU frequency is 400 x 5.0 = 2.0 Ghz.

The 533 FSB CPU's actually have a smaller multiplier inside. A 2.0 Ghz clock is generated from 533 FSB * 3.75 (smaller multiplier) = 2.00 Ghz inside the CPU.

People who are pin-modding are telling the CPU to accept a 533 Mhz bus clock, that's all. Then the internal multiplier hypes-up the clock rate to something fantastic, like a 1.8 Ghz CPU @ 400 FSB has a multiplier of 4.5, when you put this into a 533 FSB system you get an overall clock speed of 533 x 4.5 = 2.4 Ghz (NOTE I HAVE NOT DONE THIS ITS WHAT HAPPENS IN THEORY).

So it should work. I believe that the CPU's can detect when the frontside bus is too fast (i.e. 533 Mhz FSB), but there is little to no reason for Intel to put a circuit into a CPU to prevent it from running too slowly (like 400 Mhz FSB) that would be stupid and pointless...

[ajkula66]

I think it will work, and I think you guys are mistaken.

It will boot and run, but not at full speed. That's what I meant with the "not properly" statement.

The only way to get the full speed out of a 533MHz CPU on a 400MHz board is via pinmod. No ifs, ands or buts.

[systemBuilder]

Many people prefer to have their CPUs run at 1.8 Ghz and below so that their thinkpad does not heat up. If you put a 2.26 Ghz Dothan 780 into a 400 FSB bus machine like a T42, you will have a machine running at 1.7 Ghz, which would probably be satisfiably fast for many people.

For every 5% increase in CPU speed you only get about 3-4% increase in benchmark speed so the difference between a 1.7 Ghz and 2.26 Ghz CPU is only in the low-20% range. For many people, I predict it will be worthwhile - for $40 (used dothan 780) - to keep the laptop eligible to run the latest OS's from microsoft.

I have already seen many web articles for ways to turn off Metro or ways to put the Windows-7 features back into Windows-8 with add-on software. Windows 8 is not as much of an abortion as Vista was.