Probably, nobody tried this combination, so I tried it myself. There is a problem:
My satellite has two 256 PC2100 chips already installed, when I replace both with two Geil 512MB PC3200 chips, I get no display on the laptop.
On the other hand, if I replace only one 256 PC2100 chip with Geil 512MB PC3200 chip then my computer boots properly and displays 768MB RAM in the configuration.
I tried various combinations and only when I use both PC3200 chips, it won't boot.
Thanks in advance