PC100 and PC133 RAM on a 100 MHZ FSB

[PeterGriff]

For memory upgrades I buy PC133 SDRAM, and as a general rule this works in any machine whether it has a FSB of 133 or lower. I have come across a small number of machines that refuse to accept PC133 memory and will only accept PC100 RAM. They have been HP and Compaq machines of late Pentium II vintage if I remember correctly. Does someone have a technical explanation for this??

Peter G

 

[mjinks61]

It is most likely due to the practice of HP and Compaq putting a lot of proprietary components in their systems.

Those two computer makers' hardware doesn't play nice with other peoples a lot of the time.

By the way, Compaq is owned by HP.

Good luck, and Happy Computing

 

[cdogg]

At the time that 100MHz frontside buses were part of the mainstream, HP and Compaq were still separate companies (HP didn't merge with Compaq until September of 2001).

Yes, both companies tend to use proprietary components, but no one is worse than Compaq. Buying 3rd-party memory for their systems is always hit & miss.

However, the general rule is that "double-sided" PC133 memory modules work best in older systems with a 100MHz bus. That's because double-sided DIMMs are less dense. The more dense the module, the lower the chance of compatibility on older motherboards (whether it be HP, Compaq, etc...)

There really isn't too much of a science to it. If you know the system is running a 100MHz frontside bus before you buy the memory, just make sure it's PC100.

http://www.crucial.com

has a decent configurator to help you select the right modules for each system.


~cdogg
[tab]"The secret to creativity is knowing how to hide your sources"
[tab][tab]- A. Einstein

 

[Cosecha]

Is that Peter Griff from Wamsutta (Massachusetts)?

...Scott Jarvis

 

[PeterGriff]

Thanks for the feedback - I will have experiment with single-sided vs double sided if I get a chance (thanks for the tip cdogg).

(and no - Peter Griff from Australia).

Peter G