I have some RAM chips that I suspect are compatible with the central. The chips are marked with:

IC42S16400-6T
PB2645111 0307

I also have the datasheets for both the stock chip (listed above in this thread) and the suspected compatible chip. Could one of you hardware gurus take a peek and let me know if you think the chips are compatible?

Edit: I checked the form factor and the pin out, and they seem to be the same.