I need to run VMware Fusion with Win-XP for work purposes, with mail, safari, etc running as well. XCode and Adobe illustrator are probably the most resource demanding Mac Apps I run simultaneously with VMWare. VMWare is on all the time. My macbook (2GHz, 2GB memory) is rather sluggish in these tasks, while my iMac (2.8 GHz, 4 GB memory) is much faster and more responsive. But I am not sure if this is due to the extra memory or the additional CPU speed. Since a long time I want to replace this macbook which is just falling apart and the new MacBook Air's might push me over the edge. The old 12" powerbook is back it seems. However the CPU is much slower than what I have on the macbook. Will 4 GB of memory and a SSD disk make up for what I lose in CPU speed? What is the minimum CPU required to run what I described above?