Intel has a plethora of desktop processors on the market. While there are still some Pentium 4 and Pentium D processors around, the majority builds on the Core micro-architecture. We clearly recommend against purchasing any Pentium 4 or Pentium D processor, although their clock speeds of up to 3.8 GHz may look attractive. Any Core 2 processor at 2.2 GHz and up is capable of beating even the fastest Pentium D models (so does the Athlon 64 X2), because Core 2 offers much better performance per clock. Have a look at our CPU Charts to compare Pentium D and Core 2 Duo processors along with most AMD CPUs.

Thanks to its lower clock speed levels, Core 2 is more energy efficient. While the Pentium D 800 top models used to eat up to 130 W, only a Core 2 Extreme quad core can exceed 100 W. All dual-core processors are rated at 65 W. In addition, the idle power requirement of a Core 2 Duo processor is even lower, which is also due to the reduced idle clock speed (max. 1.2 GHz for Core 2 Duo/Quad versus 2.8 GHz for Pentium D/4 processors). The reduced power consumption is also made possible by improved transistor designs with reduced leakage current.

Right now, there are E and X models available. E represents the mainstream processors while X stands for Extreme Editions. A Q stands for a quad core, which Intel builds by putting two dual-core dies into one physical processor package. E6000 processors have 4 MB L2 cache if their model number is >E6400, or if it ends on -20 (e.g. E6320). Models ending on -00 (e.g. E6600) run at 266 MHz system clock speed (FSB1066), while the -50 parts (E6750) are specified for 333 MHz (FSB1333). The latter requires a P35 or X38 chipset and delivers marginally better performance. E4000 runs at 200 MHz system speed (FSB800) and only has 2 MB L2 cache. The 1 MB versions are being sold as Pentium Dual Core E2140, E2160 and E2180, running at 1.6 to 2.0 GHz. Apart from the name and some features that Intel disabled for the low-cost models, these Pentium Dual Cores are identical to Core 2 Duo devices.