|Level 2 (L2) cache||up to 4 MB||2 MB|
The Core 2 Duo chip (code named Merom) has many of the same features as its Core Duo predecessor (code named Yonah): a 667-MHz frontside bus, the 945 chip set, the 3945ABG wireless chip set, and similar clock speeds. The two biggest improvements are the doubling of Level 2 cache to 4MB in the T7000 line, and support for 64-bit processing. The latter brings Intel back on par with AMD's Turion 64 X2 chip and means users can take advantage of 64-bit applications, including the 64-bit version of Windows Vista. Core Duo cannot do 64-bit computing.
Compared to Intel Core Duo, Intel Core 2 Duo has larger L2 cache, slightly deeper pipeline and added decode and execution units. In addition, Core 2 Duo features more aggressive pre-fetch mechanisms than Core Duo, as well as Intel’s Memory Disambiguation technology that allows for out-of-order loads. In other words, not only is Core 2 Duo able to process more data at once, at a faster speed, but it can also get access to that data quicker.
Several reviewers and magazine editorial teams have performed benchmark tests to measure the performance of Core Duo and Core 2 Duo processors. Core 2 Duo processors are supposed to have about 20% higher clock speeds.
In general, Core 2 Duo gives better performance for highly CPU-intensive tasks such as 3D graphics and CPU-intensive games. However, for most ordinary applications such as word processing and web browsing, there is negligible difference in the performance of Core Duo and Core 2 Duo.
edit Power Consumption / Battery Life
Power consumption is pretty much identical for both Core Duo and Core 2 Duo. This means that the Core 2 Duo gives slightly better CPU performance without sacrificing battery life.