Powerbook titanium Can I do this

It will work only if the memory in the 500 is PC133, required by the 667, otherwise it will not work. The best way to find out is either through System Profiler, or looking on the memory itself, because it will have a sticker saying weither or not it is PC100 or PC133.

TEG

A lot of PC100 RAM will still run at 133 mhz. If I were you, I'd first do what the previous poster stated (check to see the markings on the stick of memory). If it says 133, you're golden. If not, I would actually put the PC100 stick into the 667 mhz book. The WORST that will happen is that it will crash or be unstable. If that's the case, take the stick out and you're good to go. I have a lot of experience with overclocking PCs and such so i'm telling you from experience. Good luck!

Originally posted by spaceballl
A lot of PC100 RAM will still run at 133 mhz.

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it might work, but you will most likely effectively reduce the speed of your bus to 100mhz. unless you really need more ram, this will probably slow your computer down in all but the most memory intensive applications.

but, according to this apple article:

Important:

PC100 DIMMs will not work in the 667-MHz model.

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idkew's information is false, actually.

Your computer runs at 667 mhz. That is a 133 mhz front side bus with a multiplier of 5. (do the math: 133.33333 x 5). Your processor is hardwired to run at this speed. Regardless of what speed memory you put into the powerbook, it will still run at 133 x 5. If you put PC166 memory which is specicifed to run at 166 mhz, because your bus is at 133 mhz, it will run at 133 mhz.

the PCXXX number is just a specification. Memory manufacturers make memory and they test it at various speeds. If the memory runs at 133 mhz, they slap a PC133 label on it. If the memory runs at 166 mhz, they slap a PC166 label on it. However, often their settings are very conservative and memory can run faster than it is specified for. If it does not work, your computer will crash. That's it. Your computer WILL NOT slow down, however. That is completely false.