Simon Royal <mail at simonroyal.co.uk> writes: > So my question is, can I put a 550Mhz logic board into my 400Mhz > machine? If not why not? It's been a long time since I've dealt with these, but I'm 99.9% sure they are incompatible. One reason that occurs is that the DVD drive is different; the 550/667 drive was smaller, and I think with a different connector. Kynan