RAM upgrade - 266 or 533mhz? PC2-4300 or 4200?

I want to upgrade the RAM in a Toshiba Satellite M70 SR3 Laptop.
SIW diagnostic software gives me the following info about the current RAM:
Capacity: 512MB; Type: DDR2 (PC2-4300); Speed: 266Mhz (DDR2 533); Supported Frequencies: 200.0 MHz, 266.7 MHz, 266.7 MHz.

The CPU is an Intel Pentium M 740, and the FSB speed is 532.0 MHz

I've been looking for replacement RAM (2x1GB), but the specs never seem to match exactly.

Is PC2-4300 the same as 4200? I read one forum post that said they're interchangeable. Often the speed on PC2-4300 or 4200 RAM is listed as 533Mhz. Some references say that a listed RAM speed of 266Mhz means an "actual" speed of 533Mhz, which is confusing. Is that what the "DDR2 533" in the specs means?

Will I be able to install 533Mhz RAM? Does the fact that the motherboard FSB is 533 Mhz matter?

Any and all replies welcome.


2 answers Last reply Best Answer
More about upgrade 533mhz 4300 4200
  1. Best answer
    Any DDR2 memory up to 533 will work fine.

    DDR is the short for Double Data Rate, so the "Actual" speed in diagnostic programs will always be half of the advertised, but the "Effective" speed is 533mhz.

    And yes PC2-4300 and PC2-4200 are interchangeable.
  2. Best answer selected by dave_t0661.
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