After relatively slow start quad-core processors are beginning to rapidly gain popularity among various customers. Paul Otellini, chief executive of Intel Corp. said during a conference with financial analysts on Tuesday that shipments of chips with four processing engines topped three million units last quarter.

“We launched our first quad-core processor in November of last year, and by the [end of the] second quarter [we] had shipped our first million units. With demand for our quad-core products accelerating, we shipped over 2 million units in the third quarter alone. We now offer over 20 unique quad-core processor designs,” said Mr. Otellini during the conference call with financial analysts.

Growing demand towards quad-core microprocessor is a result of relatively moderate pricing on them, which begins at $266 for Intel Core 2 Quad Q6600 as well as availability of software that takes advantage of multi-core chips.

Current quad-core processors from Intel use multi-chip-package technique and incorporate two dual-core processors onto a single piece of substrate. Given that it is considerably easier to manufacture two relatively low-power monolithic dual-core dice than to produce one monolithic quad-core product, Intel’s approach not only allowed the company to roll-out quad-core products back in November 2006, but also does seem to make more sense from economic point of view compared to monolithic designs praised by Advanced Micro Devices due to the fact that potentially such quad-core chips have considerably higher yields compared to AMD’s.

The new quad-core AMD Opteron and the forthcoming quad-core AMD Phenom processors use monolith implementation, which means that all the cores are incorporated into a single piece of silicon. AMD claims that its quad-core CPUs can deliver better performance and scalability.

Since the demand towards quad-core processors is only likely to continue accelerating, AMD will have rapidly ramp up output of such chips in order to increase its average selling prices.