Intel officially closed the books on the Pentium era on Thursday with the Core 2 Duo, its most important product launch in 13 years. Two classes of Core 2 Duo processors were released Thursday. PCs based on the Core Extreme processor are available immediately. However, ‘Extreme’ is an appropriate description for both the performance and price of those systems, and they are only appropriate for the deep-pocketed performance-starved user. Mainstream systems at more affordable prices will start to appear in early August, Intel CEO said.