IBM/Lenovo's memory spec

[vinuneuro]

I was looking at the specs for this T60 and the memory specs they call for seem a little strange. Maybe someone can clarify it.

Why does it say to use PC2-4200 533mhz if you're using a 2gb stick and 667 PC2-5300 for the rest?

Usually, you want to match speeds between the slots right, so how would 3gb total be possible following what they call for?

Also, how crucial is it to have the same size, speed, brand in both slots?

Thanks!

_____

Memory

* PC2-5300 Non-Parity (NP) Double Data Rate Two (DDR2) Technology
o The use of 667 MHz SO DIMM memory is recommended for this system.

* 256 MB, 512 MB, 1 GB, or 2GB memory
* Supports up to 4GB maximum memory
Note: Only 64-bit operating systems support more than 3GB of system memory (RAM). Intel Chipsets 945GM and 945PM do not support more than 3GB system memory (RAM), even when a 64-bit operating system is installed.

o Recommended for memory expansion are 2 GB PC2-4200 DDR2 SDRAM 533 MHz SO DIMM or 256 MB, 512 MB, and 1 GB PC2-5300 DDR2 SDRAM 667 MHz SO DIMM.

[Harryc]

http://forum.thinkpads.com/viewtopic.php?f=29&t=77690

[vinuneuro]

Thanks I did find that thread earlier. Didn't go through patiently enough, it answered all my questions this time.