Memory speed for 440 chipset

[byGeorge]

I have a 440 chipset based spare laptop (Dell Latitude LS) that has a 100mhz bus. I need to upgrade the 144 pin SODIMM SDRAM memory from 128M to 256M (the maximum). My trusty source (Crucial) selected an appropriate module but they have no stock. Interestingly they chose a PC133 module. Some of the sites that I have looked at state that you CANNOT substitute PC133 memory for a PC100 application even though Crucial did so. Others state that a PC133 module will just run slower on a 100Mhz bus. The catch is that PC100 memory is 2X the price of PC133. I looked at the existing module and it is labled as PC100 but the individual DRAM chips look like PC133 if I understand my part number decodes correctly (-75B).

Can I use either a PC100 or PC133 module?

Computer specs:

Dell Latitude LS
400 Mhz PIII
100 bus
256M maximum memory
1 slot
82443BX
82371MB


Thanks,

[rjs735]

The 133 will run at the speed of the older 100. The only reason they would suggest the 133 is because they don't make the 100 anymore. Crucial is the MFG arm od Micron chips. If I remember correctly.

You can use a 133 in place of a 100 safely.

[byGeorge]

Thank you for the reply. Any idea why PNY has the following warning on their PC133 ordering page?

"Important: This PC133 Module is not backward compatible with PC100 Machines. For a PC100 compatible version of this module please click here. To determine the correct memory upgrade for your machine, use the PNY memory configurator."

BTW, the hot link sends you to the PC100 page for 2X the price.

UPDATE:

Crucial says that not all PC133 memory modules are created equal. If they are based on "high density" memory, they will not be backward compatible to a 100 Mhz bus based machine, it will not recognize the memory. The module must be based on standard density memory which is becomming increasingly rare.

Thanks,