Advanced Micro Devices and Intel Corporation have both increased the lead in the CPU market late last year, according to the figures by market research firm Mercury Research.

Intel saw its market share inch up to 82.2% in the fourth quarter, up from 82% in the previous quarter. Meanwhile, the market share for rival Advanced Micro Devices climbed to 16.6%, up from 16%, according to a news-story by CNET News.com. Both leading chipmakers gained their presence in the x86 market at the expense of Transmeta and VIA Technologies, who now command 1.2% of the market.

Unfortunately for AMD, the majority of its shipments during the quarter were AMD Sempron microprocessors designed for entry-level personal computers, according to Dean McCarron, head analyst at Mercury Research. Despite of the success AMD Athlon 64 and AMD Opteron processors face, large computer makers still produce the majority of their high-end PCs with Intel Pentium 4 or Intel Xeon processors inside. Furthermore, sometimes AMD even cannot supply enough of its high-performance products.

Even though market research company claims that AMD’s market share increases are driven by entry-level products, it should be noted that since last year AMD has started to supply AMD Opteron and AMD Athlon 64 products to the retail channel as well as to leading makers of personal computers, workstations and servers, such as HP, IBM, Gateway, Fujitsu-Siemens and a number of others. This has impact on AMD’s margins and profitability.

PC processor market share figures include desktop, notebook and server processors. Desktop processors shipments usually outnumber the other two categories combined, however in the Q4 2004 research firms like Gartner said notebooks were selling exceptionally well, which boosted market share for Intel and may have hid AMD’s success in the desktops.