Quad-core processors, which are fairly commonplace in desktop PCs, will be in almost half of all notebooks sold within the next four years, according to market research firm IHS iSuppli.

In a report July 12, IHS iSuppli analysts said that by 2015, 49 percent of all notebooks will ship with quad-core processors. That will be up from about 9 percent this year, according to the analysts. In total, 160 million notebooks powered by quad-core chips will ship in 2015, up from 21.1 million this year.

Six-core chips also will make inroads, the analysts said. Currently there are no notebooks with six-core processors, they said. That will change by 2015, when 18 percent of notebooks will ship with six-core chips.

In 2015, 58.9 million notebooks will boast six-core chips, according to IHS iSuppli.

The numbers represent a natural progression, as chip makers like Intel and Advanced Micro Devices look to improve chip performance through the use of more cores rather than upping the chip’s frequency, according to Matthew Wilkins, principal analyst of compute platforms for HIS iSuppli.

“The cornerstone of PC performance, the microprocessor, is continuing to evolve to provide new levels of performance to the PC market,” Wilkins said in a statement. “For decades, the main focus for increasing microprocessor performance was in the area of clock speed, with suppliers battling to offer parts with the most megahertz or gigahertz. However, the competition now has shifted to the battle over cores, with suppliers racing to offer parts that boost performance by providing greater parallelism. The battle now has moved from the dual-core segment into the quad-core area—and next will spread to the six-core realm.”

IHS iSuppli analysts pointed to recent chip releases—such as Intel’s six-core Core i7-970 and AMD’s six-core Phenom II X6—as examples of offerings to come. Currently they’re aimed at desktops, but the chip makers will bring higher core counts to notebook processors as well.

Such chips are examples of the ongoing development of PC technology, even at a time when consumers are turning their attention to tablets, particularly Apple’s iPad. Both IDC and Gartner in April noted that in the first quarter, the worldwide PC market saw its first year-over-year decline in six quarters, due in large part to consumer interest in tablets.

“‘Good-enough computing’ has become a firm reality, exemplified first by [netbooks] and now media tablets,” IDC senior research analyst Jay Chou said in a statement at the time. “Macroeconomic forces can explain some of the ebb and flow of the PC business, but the real question PC vendors have to think hard about is how to enable a compelling user experience that can justify spending on the added horsepower.”

Despite the pressure on the market, PC OEMs and chip makers continue to improve the performance, design and features in the systems, IHS iSuppli analysts said. They also evolving the notebooks to fit user demands for all-day mobile computing. An example of that is in the move to integrate graphics technology onto the same piece of silicon as the CPU, which helps with power consumption.

Intel—which is the world’s top chip maker with 82.6 percent of the market, according to HIS iSuppli—is offering integrated graphics in its chips based on the new “Sandy Bridge” architecture, while AMD does the same with its Fusion APUs (accelerated processing units). Both vendors launched their integrated-graphics offerings at the 2011 Consumer Electronics Show in January. AMD is the world’s second-largest chip vendor, with 10.1 percent of the market.