Max is completely cross platform, so compatibility would not be an issue. In terms of performance, it entirely depends on the specification of the machine. Generally speaking, it should have more than enough processing power to handle most patches and systems.
Max/MSP is a RAM hungry program due to the nature of the architecture, so you should ensure that there is at least 4GB to be safe.
Depending on the use you might not need that much memory. My Intel Macbook runs the performance patches I need just fine with 2GB of memory and has a 2.16GHz processor. Some rudimentary googling suggests the 2005 model shipped with only 512MB of RAM so an upgrade there may still be worth thinking about.