Marcos, I would go with the dual, since the apps you want to use should take good advantage of dual processors. Also, the larger L3 cache of the 7455 makes a significant difference in streaming video. I have a Dual 800 Quicksilver G4 that I upgraded to a dual 1800. Although most operations are faster, the original CPU card with larger L3 cache actually outperforms the newer card in streaming tasks. HTH, Rick On Nov 28, 2006, at 9:41 AM, marco santos wrote: > a> DUAL G4-7455/1.0GHz with 256K L2 On-Chip & 2MB L3 > Cache Per Processor OR > b> G4 1.8GHz (1800MHZ) Processor Upgrade (NOT DUAL)