Pentium M or Pentium 4 M

spaceballs · 03-21-2006, 03:06 AM

While compiling, there is an option under processor type for Pentium M or Pentium 4 M. I was under the impression that there wasn't a distinction and that all Pentium M's were the same.

That got me to thinking...what actually happens when you select he correct processor type when compiling? What would happen if you selected the wrong processor?

nx5000 · 03-21-2006, 06:59 AM

If you have a notebook chip, you should choose Pentium M.
This enabled cc option -mtune=pentium3

If you have a Pentium-4 M (Mobile with Hyperthreading like 2.2Ghz) , Pentium4,.. then cc option is -mtune=pentium4

On newer gcc, mtune= is replaced by mcpu=

If you select wrong options, you might get slow kernel or crash

raska · 03-21-2006, 09:18 AM

Quote:

Originally Posted by spaceballs

...I was under the impression that there wasn't a distinction and that all Pentium M's were the same...

no sir,

- Pentium M (aka Centrino) is a remasterized Pentium III-coppermine without HyperThreading Technology (HTT)

- Pentium 4M is properly a Pentium 4 with movility options like frequency/voltage control (Speedstep, called by Intel; PowerNow! or Cool 'n' Quiet, called by AMD) which were first introduced on those Pentium III-coppermine

nx5000 · 03-21-2006, 09:41 AM

Pentium4M has a Northwood core, 8Kb L1 cache, 512Kb L2 cache and SpeedStep 2. Runs at 2.2Ghz => low autonomy. You can overclock it to 3Ghz you will get good performance but very very low autonomy.

While the Pentium M has a bania core, 32Kb L1 cache, 1024Kb L2 cache and SpeedStep 3. Runs at max 1.6Ghz