PC4200 RAM backward compatible?

[Naimfan]

All--

I tried the search engine, but didn't find anything, even though I suspect this question has been asked and answered before.

So--here's the question: Can I use a 1 GB stick of PC4200 RAM in a 1.33 GHz 15" PB? My PB uses PC2700 RAM, I'm hoping I can substitute the PC4200 RAM because it's a fraction of the cost (I understand that even if it works it will be limited speed-wise by the PB's architecture).

Thanks in advance!