Yes, GHz is your processors speed, which will also affect your systems performance (its not really upgradeable though, unless you buy a new motherboard). A 1.8 GHz is a pretty good speed, especially compared to lazyturbos 650 MHz system. (1 GHz = 1000 MHz). Although I do have a 333MHz system that runs great when its stacked with over 512MB of memory. I run a 2.4 GHz system with 1GB of ram and its great. I believe the maximum you can get these days is about 3.2 GHz (spelled Gigahertz btw).