Since my Santa give me a really good gift rather than a MacBook, I have to continue use my old laptop IBM T40 with 1.3G PM and 512MB memory. Then I decide to upgrade it. It's really hard to find a mobile cpu with a reasonable price two years ago, however you can easy find one today. I order a Dothan 755 with 90nm 2.0G 400MHZ(Spec SL7EL), in 6xx RMB (a new one is around 9xx I guess). T40 mainboard can only support 400MHZ Dothan, A little pity.
If you have an old T40 as well, and want to upgrade to an Dothan, please notice that you have to order a stepping B1 version CPU (not C0). Otherwise you can only work in a low frequency. The reason is IBM T40 Embedded Controller don't update for a long time. The last update is Nov 2004, however C0 CPU is available in June 2005 ! So the best CPU you can buy should be 765 2.1G SL7V3. Or someday IBM update EC for the old T40.
The old cpu I plan to make a key ring :-)
