Shares of microprocessor leaders Intel and Advanced Micro Devices both surged more than five percent in Wednesday's advance despite slowing sales of PCs.

Shares of Intel, the world's top chip maker closed at $24.91, up 4.6 percent, while those of smaller rival AMD closed up 6.95 percent at $5.69.

Overall stock markets rose more than 4 percent after the U.S. Federal Reserve and foreign central banks took steps to propel global economic growth.

While both Santa Clara, Calif.-based Intel and Sunnyvale, Calif.-based AMD reported solid third-quarter results, those of two of their biggest PC customers, Hewlett-Packard and Dell, showed only tepid gains as consumers shift quickly from PCs to smartphones and tablets.

To be sure, HP, the world's biggest computer company, and IBM, No. 2, both reported strong gains in third-quarter shipments of servers and advanced computers that gang together many microprocessors. Armonk, N.Y.-based IBM, as well, as among the world's largest chipmakers.

IBM shares rose 3.9 percent to $188.

To deal with changing preferences, both Intel and AMD have announced new products. Intel, with its Ultrabook campaign, has said it expects as many as 50 customers to display new ultra-light and tablet-like products at the January Consumer Electronics Show. Intel has also hooked up with Microsoft to develop new chipsets for Windows-based tablets due for later-2012 delivery.

Among companies planning to re-enter the tablet sector is HP, whose TouchPad product was withdrawn after a September fire sale.

AMD, meanwhile, under new CEO Rory Read, a former president of China's Lenovo Group, now the No. 2 PC maker, plans to ship its new Trinity product line of accelerated processing units for laptops in early 2012 but will devote more effort to selling more powerful processors for servers because they command a higher margin.

AMD's director of field application engineering Greg Poole told ZDNet Asia the chipmaker wants to target servers because server processors are mission critical and do more for customers. In the third quarter, AMD's computing solutions segment that includes server chips reported revenue of $1.3 billion, a five percent gain over 2010.

Intel's market capitalization is $126.8 billion, compared with AMD's $3.97 billion.